Patent Publication Number: US-2022236396-A1

Title: Line of sight determination

Description:
BACKGROUND 
     Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks), a third-generation (3G) high speed data, Internet-capable wireless service, a fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax), a fifth-generation (5G) service, etc. There are presently many different types of wireless communication systems in use, including Cellular and Personal Communications Service (PCS) systems. Examples of known cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Time Division Multiple Access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, etc. 
     A fifth generation (5G) mobile standard calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with 1 gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards. 
     SUMMARY 
     In an embodiment, a UE (user equipment) includes: a memory; a wireless transceiver; a directional, reflection-based ranging system configured to determine directions between the UE and reflectors and corresponding distances between the UE and the reflectors; and a processor, communicatively coupled to the memory, the wireless transceiver, and the directional, reflection-based ranging system and configured to: obtain, from the ranging system (1) a first direction, between the UE and a particular reflector, and (2) a first distance, between the UE and the particular reflector, corresponding to the first direction; determine, based on a positioning reference signal (PRS) received by the wireless transceiver from a PRS source (3) a second direction, corresponding to an angle of arrival of the PRS at the UE, and (4) a second distance, traveled by the PRS from the PRS source to the UE, corresponding to the second direction; and determine whether the second distance is a line-of-sight distance between the UE and the PRS source based on the first direction, the first distance, the second direction, and the second distance. 
     Implementations of such a UE may include one or more of the following features. The processor is configured to determine that the second distance is the line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being within a second threshold closeness. The processor is configured to determine the first threshold based on an angular accuracy of the second direction. The processor is configured to determine the first threshold based on a quantity of antenna elements of the wireless transceiver used to receive one or more PRS. 
     Also or alternatively, implementations of such a UE may include one or more of the following features. The processor is configured to determine that the second distance is a non-line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being outside of a second threshold closeness. The processor is configured to send a report, via the wireless interface, including position information determined from the one or more PRS and at least one line-of-sight/non-line-of-sight indication indicating whether the position information is based on a line-of-sight measurement or a non-line-of-sight measurement. The position information includes a location estimate of the UE. The processor is configured to: obtain, from the ranging system (5) a plurality of first directions between the UE and a corresponding plurality of reflectors, and (6) a plurality of first distances corresponding to the plurality of first directions; and determine whether the second distance is the line-of-sight distance between the UE and the PRS source without using any of the plurality of first direction indications based on the second direction being outside a threshold closeness with respect to each of the plurality of first directions. 
     In an embodiment, a UE includes: means for transmitting a ranging signal and receiving a reflection of the ranging signal; means for determining, based on the ranging signal and the reflection of the ranging signal, (1) a first direction, between the UE and a reflector, and (2) a first distance, between the UE and the reflector, corresponding to the first direction; means for determining, based on a positioning reference signal (PRS) received by the UE from a PRS source, (3) a second direction, corresponding to an angle of arrival of the PRS at the UE, and (4) a second distance, traveled by the PRS from the PRS source to the UE, corresponding to the second direction; and means for determining whether the second distance is a line-of-sight distance between the UE and the PRS source based on the first direction, the first distance, the second direction, and the second distance. 
     Implementations of such a UE may include one or more of the following features. The means for determining whether the second distance is the line-of-sight distance between the UE and the PRS source include means for determining that the second distance is the line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being within a second threshold closeness. The UE includes means for determining the first threshold based on an angular accuracy of the second direction. The means for determining the first threshold include means for determining the first threshold based on a quantity of antenna elements of the means for determining the second direction between the UE and the PRS source. 
     Also or alternatively, implementations of such a UE may include one or more of the following features. The means for determining whether the second distance is the line-of-sight distance between the UE and the PRS source include means for determining that the second distance is a non-line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being outside of a second threshold closeness. The UE includes means for sending a report including position information determined from the one or more PRS and at least one line-of-sight/non-line-of-sight indication indicating whether the position information is based on a line-of-sight measurement or a non-line-of-sight measurement. The position information includes a location estimate of the UE. 
     In an embodiment, a method of determining a line-of-sight relationship between a UE and a PRS source includes: transmitting a ranging signal; receiving a reflection of the ranging signal; determining, based on the ranging signal and the reflection of the ranging signal, (1) a first direction, between the UE and a reflector, and (2) a first distance, between the UE and the reflector, corresponding to the first direction; determining, based on a PRS received by the UE from the PRS source, (3) a second direction, corresponding to an angle of arrival of the PRS at the UE, and (4) a second distance, traveled by the PRS from the PRS source to the UE, corresponding to the second direction; and determining whether the second distance is a line-of-sight distance between the UE and the PRS source based on the first direction, the first distance, the second direction, and the second distance. 
     Implementations of such a method may include one or more of the following features. Determining whether the second distance is the line-of-sight distance between the UE and the PRS source includes determining that the second distance is the line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being within a second threshold closeness. The method includes determining the first threshold based on an angular accuracy of the second direction. Determining the first threshold includes determining the first threshold based on a quantity of antenna elements used to determine the second direction between the UE and the PRS source. 
     Also or alternatively, implementations of such a method may include one or more of the following features. Determining whether the second distance is the line-of-sight distance between the UE and the PRS source includes determining that the second distance is a non-line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being outside of a second threshold closeness. The method includes sending a report including position information determined from the one or more PRS and at least one line-of-sight/non-line-of-sight indication indicating whether the position information is based on a line-of-sight measurement or a non-line-of-sight measurement. The position information includes a location estimate of the UE. 
     In an embodiment, a non-transitory, processor-readable storage medium includes processor-readable instructions to cause a processor of a UE, in order to determine a line-of-sight relationship between the UE and a PRS source, to: transmit a ranging signal; determine, based on the ranging signal and a reflection of the ranging signal received by the UE, (1) a first direction, between the UE and a reflector, and (2) a first distance, between the UE and the reflector, corresponding to the first direction; determine, based a PRS received by the UE from the PRS source, (3) a second direction, corresponding to an angle of arrival of the PRS at the UE, and (4) a second distance, traveled by the PRS from the PRS source to the UE, corresponding to the second direction; and determine whether the second distance is a line-of-sight distance between the UE and the PRS source based on the first direction, the first distance, the second direction, and the second distance. 
     Also or alternatively, implementations of such a storage medium may include one or more of the following features. The instructions to cause the processor to determine whether the second distance is the line-of-sight distance between the UE and the PRS source include instructions to cause the processor to determine that the second distance is the line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being within a second threshold closeness. The instructions include instructions to cause the processor to determine the first threshold based on an angular accuracy of the second direction. The instructions to cause the processor to determine the first threshold include instructions to cause the processor to determine the first threshold based on a quantity of antenna elements used to determine the second direction between the UE and the PRS source. 
     Also or alternatively, implementations of such a storage medium may include one or more of the following features. The instructions to cause the processor to determine whether the second distance is the line-of-sight distance between the UE and the PRS source include instructions to cause the processor to determine that the second distance is a non-line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being outside of a second threshold closeness. The instructions include instructions to cause the processor to send a report including position information determined from the one or more PRS and at least one line-of-sight/non-line-of-sight indication indicating whether the position information is based on a line-of-sight measurement or a non-line-of-sight measurement. The position information includes a location estimate of the UE. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified diagram of an example wireless communications system. 
         FIG. 2  is a block diagram of components of an example user equipment shown in  FIG. 1 . 
         FIG. 3  is a block diagram of components of an example transmission/reception point shown in  FIG. 1 . 
         FIG. 4  is a block diagram of components of an example server shown in  FIG. 1 . 
         FIG. 5  is a block diagram of an example user equipment. 
         FIG. 6  is a signaling and process flow for determining line-of-sight status of a positioning reference signal source, determining position information, and determining map information. 
         FIG. 7  is a simplified diagram of an environment of a target user equipment (UE), anchor UEs, and buildings. 
         FIG. 8  is a simplified diagram of a memory containing databases of ranging-system-determined angles and distances to reflectors, and positioning-reference-signal-based angles of arrival of signals from, and distances to, sources of positioning reference signals. 
         FIG. 9  is a block flow diagram of a method for determining a line-of-sight relationship between a user equipment and a positioning reference signal source. 
     
    
    
     DETAILED DESCRIPTION 
     Techniques are discussed herein for determining whether signals received from a signal source were line-of-sight transmissions, i.e., followed a line-of-sight path from source to receiver. For example, a reflection-based ranging system of a user equipment may determine angles and distances from the user equipment to a reflector. The user equipment may also determine angles of arrival of positioning reference signals (PRS) from respective sources and determine distances traveled by the positioning reference signals. By comparing the angles of arrival to the ranging-system-determined angles and the respective distances, whether the positioning reference signals traveled line-of-sight (LOS) paths can be determined. For example, if an angle of arrival corresponds (is close) to a ranging-system-determined angle, and the corresponding distance traveled by the PRS corresponds (is close) to the respective ranging-system-determined distance, then the PRS can be identified as having traveled an LOS path. If the angles correspond but the distances do not, then the PRS can be identified has having traveled a non-line-of-sight (NLOS) path. If the angle of arrival does not correspond to a ranging-system-determined angle, then LOS/NLOS status of the PRS path can be identified as uncertain, in which case one or more other techniques in addition to or instead of the above techniques may be used to determine the LOS/NLOS status of the PRS path. These are examples, and other examples may be implemented. 
     Items and/or techniques described herein may provide one or more of the following capabilities, as well as other capabilities not mentioned. Accuracy of determined position information may be improved. Radio frequency fingerprinting can be improved, e.g., by providing LOS/NLOS and transmit/receive location pair information (indicating transmit/receive information and an LOS/NLOS flag (of whether there is LOS or NLOS at that(those) location(s))) and/or providing information regarding angles and distances to reflecting objects. Other capabilities may be provided and not every implementation according to the disclosure must provide any, let alone all, of the capabilities discussed. 
     Obtaining the locations of mobile devices that are accessing a wireless network may be useful for many applications including, for example, emergency calls, personal navigation, consumer asset tracking, locating a friend or family member, etc. Existing positioning methods include methods based on measuring radio signals transmitted from a variety of devices or entities including satellite vehicles (SVs) and terrestrial radio sources in a wireless network such as base stations and access points. It is expected that standardization for the 5G wireless networks will include support for various positioning methods, which may utilize reference signals transmitted by base stations in a manner similar to which LTE wireless networks currently utilize Positioning Reference Signals (PRS) and/or Cell-specific Reference Signals (CRS) for position determination. 
     The description may refer to sequences of actions to be performed, for example, by elements of a computing device. Various actions described herein can be performed by specific circuits (e.g., an application specific integrated circuit (ASIC)), by program instructions being executed by one or more processors, or by a combination of both. Sequences of actions described herein may be embodied within a non-transitory computer-readable medium having stored thereon a corresponding set of computer instructions that upon execution would cause an associated processor to perform the functionality described herein. Thus, the various aspects described herein may be embodied in a number of different forms, all of which are within the scope of the disclosure, including claimed subject matter. 
     As used herein, the terms “user equipment” (UE) and “base station” are not specific to or otherwise limited to any particular Radio Access Technology (RAT), unless otherwise noted. In general, such UEs may be any wireless communication device (e.g., a mobile phone, router, tablet computer, laptop computer, consumer asset tracking device, Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communications network. A UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with a Radio Access Network (RAN). As used herein, the term “UE” may be referred to interchangeably as an “access terminal” or “AT,” a “client device,” a “wireless device,” a “subscriber device,” a “subscriber terminal,” a “subscriber station,” a “user terminal” or UT, a “mobile terminal,” a “mobile station,” or variations thereof. Generally, UEs can communicate with a core network via a RAN, and through the core network the UEs can be connected with external networks such as the Internet and with other UEs. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over wired access networks, WiFi networks (e.g., based on IEEE 802.11, etc.) and so on. 
     A base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed, and may be alternatively referred to as an Access Point (AP), a Network Node, a NodeB, an evolved NodeB (eNB), a general Node B (gNodeB, gNB), etc. In addition, in some systems a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions. 
     UEs may be embodied by any of a number of types of devices including but not limited to printed circuit (PC) cards, compact flash devices, external or internal modems, wireless or wireline phones, smartphones, tablets, consumer asset tracking devices, asset tags, and so on. A communication link through which UEs can send signals to a RAN is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the RAN can send signals to UEs is called a downlink or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein the term traffic channel (TCH) can refer to either an uplink/reverse or downlink/forward traffic channel. 
     As used herein, the term “cell” or “sector” may correspond to one of a plurality of cells of a base station, or to the base station itself, depending on the context. The term “cell” may refer to a logical communication entity used for communication with a base station (for example, over a carrier), and may be associated with an identifier for distinguishing neighboring cells (for example, a physical cell identifier (PCID), a virtual cell identifier (VCID)) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (for example, machine-type communication (MTC), narrowband Internet-of-Things (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of devices. In some examples, the term “cell” may refer to a portion of a geographic coverage area (for example, a sector) over which the logical entity operates. 
     Referring to  FIG. 1 , an example of a communication system  100  includes a UE  105 , a UE  106 , a Radio Access Network (RAN)  135 , here a Fifth Generation (5G) Next Generation (NG) RAN (NG-RAN), and a 5G Core Network (5GC)  140 . The UE  105  and/or the UE  106  may be, e.g., an IoT device, a location tracker device, a cellular telephone, a vehicle (e.g., a car, a truck, a bus, a boat, etc.), or other device. A 5G network may also be referred to as a New Radio (NR) network; NG-RAN  135  may be referred to as a 5G RAN or as an NR RAN; and 5GC  140  may be referred to as an NG Core network (NGC). Standardization of an NG-RAN and 5GC is ongoing in the 3rd Generation Partnership Project (3GPP). Accordingly, the NG-RAN  135  and the 5GC  140  may conform to current or future standards for 5G support from 3GPP. The RAN  135  may be another type of RAN, e.g., a 3G RAN, a 4G Long Term Evolution (LTE) RAN, etc. The UE  106  may be configured and coupled similarly to the UE  105  to send and/or receive signals to/from similar other entities in the system  100 , but such signaling is not indicated in  FIG. 1  for the sake of simplicity of the figure. Similarly, the discussion focuses on the UE  105  for the sake of simplicity. The communication system  100  may utilize information from a constellation  185  of satellite vehicles (SVs)  190 ,  191 ,  192 ,  193  for a Satellite Positioning System (SPS) (e.g., a Global Navigation Satellite System (GNSS)) like the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), Galileo, or Beidou or some other local or regional SPS such as the Indian Regional Navigational Satellite System (IRNSS), the European Geostationary Navigation Overlay Service (EGNOS), or the Wide Area Augmentation System (WAAS). Additional components of the communication system  100  are described below. The communication system  100  may include additional or alternative components. 
     As shown in  FIG. 1 , the NG-RAN  135  includes NR nodeBs (gNBs)  110   a ,  110   b , and a next generation eNodeB (ng-eNB)  114 , and the 5GC  140  includes an Access and Mobility Management Function (AMF)  115 , a Session Management Function (SMF)  117 , a Location Management Function (LMF)  120 , and a Gateway Mobile Location Center (GMLC)  125 . The gNBs  110   a ,  110   b  and the ng-eNB  114  are communicatively coupled to each other, are each configured to bi-directionally wirelessly communicate with the UE  105 , and are each communicatively coupled to, and configured to bi-directionally communicate with, the AMF  115 . The gNBs  110   a ,  110   b , and the ng-eNB  114  may be referred to as base stations (BSs). The AMF  115 , the SMF  117 , the LMF  120 , and the GMLC  125  are communicatively coupled to each other, and the GMLC is communicatively coupled to an external client  130 . The SMF  117  may serve as an initial contact point of a Service Control Function (SCF) (not shown) to create, control, and delete media sessions. The BSs  110   a ,  110   b ,  114  may be a macro cell (e.g., a high-power cellular base station), or a small cell (e.g., a low-power cellular base station), or an access point (e.g., a short-range base station configured to communicate with short-range technology such as WiFi, WiFi-Direct (WiFi-D), Bluetooth®, Bluetooth®-low energy (BLE), Zigbee, etc. One or more of the BSs  110   a ,  110   b ,  114  may be configured to communicate with the UE  105  via multiple carriers. Each of the BSs  110   a ,  110   b ,  114  may provide communication coverage for a respective geographic region, e.g. a cell. Each cell may be partitioned into multiple sectors as a function of the base station antennas. Other base stations may be included in the communication system  100  such as one or more WLAN APs (wireless local area network access points). 
       FIG. 1  provides a generalized illustration of various components, any or all of which may be utilized as appropriate, and each of which may be duplicated or omitted as necessary. Specifically, although only one UE  105  is illustrated, many UEs (e.g., hundreds, thousands, millions, etc.) may be utilized in the communication system  100 . Similarly, the communication system  100  may include a larger (or smaller) number of SVs (i.e., more or fewer than the four SVs  190 - 193  shown), gNBs  110   a ,  110   b , ng-eNBs  114 , AMFs  115 , external clients  130 , and/or other components. The illustrated connections that connect the various components in the communication system  100  include data and signaling connections which may include additional (intermediary) components, direct or indirect physical and/or wireless connections, and/or additional networks. Furthermore, components may be rearranged, combined, separated, substituted, and/or omitted, depending on desired functionality. 
     While  FIG. 1  illustrates a 5G-based network, similar network implementations and configurations may be used for other communication technologies, such as 3G, Long Term Evolution (LTE), etc. Implementations described herein (be they for 5G technology and/or for one or more other communication technologies and/or protocols) may be used to transmit (or broadcast) directional synchronization signals, receive and measure directional signals at UEs (e.g., the UE  105 ) and/or provide location assistance to the UE  105  (via the GMLC  125  or other location server) and/or compute a location for the UE  105  at a location-capable device such as the UE  105 , the gNB  110   a ,  110   b , or the LMF  120  based on measurement quantities received at the UE  105  for such directionally-transmitted signals. The gateway mobile location center (GMLC)  125 , the location management function (LMF)  120 , the access and mobility management function (AMF)  115 , the SMF  117 , the ng-eNB (eNodeB)  114  and the gNBs (gNodeBs)  110   a ,  110   b  are examples and may, in various embodiments, be replaced by or include various other location server functionality and/or base station functionality respectively. 
     The system  100  is capable of wireless communication in that components of the system  100  can communicate with one another (at least some times using wireless connections) directly or indirectly, e.g., via the BSs  110   a ,  110   b ,  114  and/or the network  140  (and/or one or more other devices not shown, such as one or more other base transceiver stations). For indirect communications, the communications may be altered during transmission from one entity to another, e.g., to alter header information of data packets, to change format, etc. The UE  105  may include multiple UEs and may be a mobile wireless communication device, but may communicate wirelessly and via wired connections. The UE  105  may be any of a variety of devices, e.g., a smartphone, a tablet computer, a vehicle-based device, etc., but these are examples only as the UE  105  is not required to be any of these configurations, and other configurations of UEs may be used. Other UEs may include wearable devices (e.g., smart watches, smart jewelry, smart glasses or headsets, etc.). Still other UEs may be used, whether currently existing or developed in the future. Further, other wireless devices (whether mobile or not) may be implemented within the system  100  and may communicate with each other and/or with the UE  105 , the BSs  110   a ,  110   b ,  114 , the core network  140 , and/or the external client  130 . For example, such other devices may include internet of thing (IoT) devices, medical devices, home entertainment and/or automation devices, etc. The core network  140  may communicate with the external client  130  (e.g., a computer system), e.g., to allow the external client  130  to request and/or receive location information regarding the UE  105  (e.g., via the GMLC  125 ). 
     The UE  105  or other devices may be configured to communicate in various networks and/or for various purposes and/or using various technologies (e.g., 5G, Wi-Fi communication, multiple frequencies of Wi-Fi communication, satellite positioning, one or more types of communications (e.g., GSM (Global System for Mobiles), CDMA (Code Division Multiple Access), LTE (Long-Term Evolution), V2X (Vehicle-to-Everything, e.g., V2P (Vehicle-to-Pedestrian), V2I (Vehicle-to-Infrastructure), V2V (Vehicle-to-Vehicle), etc.), IEEE 802.11p, etc.). V2X communications may be cellular (Cellular-V2X (C-V2X)) and/or WiFi (e.g., DSRC (Dedicated Short-Range Connection)). The system  100  may support operation on multiple carriers (waveform signals of different frequencies). Multi-carrier transmitters can transmit modulated signals simultaneously on the multiple carriers. Each modulated signal may be a Code Division Multiple Access (CDMA) signal, a Time Division Multiple Access (TDMA) signal, an Orthogonal Frequency Division Multiple Access (OFDMA) signal, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) signal, etc. Each modulated signal may be sent on a different carrier and may carry pilot, overhead information, data, etc. The UEs  105 ,  106  may communicate with each other through UE-to-UE sidelink (SL) communications by transmitting over one or more sidelink channels such as a physical sidelink synchronization channel (PSSCH), a physical sidelink broadcast channel (PSBCH), or a physical sidelink control channel (PSCCH). 
     The UE  105  may comprise and/or may be referred to as a device, a mobile device, a wireless device, a mobile terminal, a terminal, a mobile station (MS), a Secure User Plane Location (SUPL) Enabled Terminal (SET), or by some other name. Moreover, the UE  105  may correspond to a cellphone, smartphone, laptop, tablet, PDA, consumer asset tracking device, navigation device, Internet of Things (IoT) device, health monitors, security systems, smart city sensors, smart meters, wearable trackers, or some other portable or moveable device. Typically, though not necessarily, the UE  105  may support wireless communication using one or more Radio Access Technologies (RATs) such as Global System for Mobile communication (GSM), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), LTE, High Rate Packet Data (HRPD), IEEE 802.11 WiFi (also referred to as Wi-Fi), Bluetooth® (BT), Worldwide Interoperability for Microwave Access (WiMAX), 5G new radio (NR) (e.g., using the NG-RAN  135  and the 5GC  140 ), etc. The UE  105  may support wireless communication using a Wireless Local Area Network (WLAN) which may connect to other networks (e.g., the Internet) using a Digital Subscriber Line (DSL) or packet cable, for example. The use of one or more of these RATs may allow the UE  105  to communicate with the external client  130  (e.g., via elements of the 5GC  140  not shown in  FIG. 1 , or possibly via the GMLC  125 ) and/or allow the external client  130  to receive location information regarding the UE  105  (e.g., via the GMLC  125 ). 
     The UE  105  may include a single entity or may include multiple entities such as in a personal area network where a user may employ audio, video and/or data I/O (input/output) devices and/or body sensors and a separate wireline or wireless modem. An estimate of a location of the UE  105  may be referred to as a location, location estimate, location fix, fix, position, position estimate, or position fix, and may be geographic, thus providing location coordinates for the UE  105  (e.g., latitude and longitude) which may or may not include an altitude component (e.g., height above sea level, height above or depth below ground level, floor level, or basement level). Alternatively, a location of the UE  105  may be expressed as a civic location (e.g., as a postal address or the designation of some point or small area in a building such as a particular room or floor). A location of the UE  105  may be expressed as an area or volume (defined either geographically or in civic form) within which the UE  105  is expected to be located with some probability or confidence level (e.g., 67%, 95%, etc.). A location of the UE  105  may be expressed as a relative location comprising, for example, a distance and direction from a known location. The relative location may be expressed as relative coordinates (e.g., X, Y (and Z) coordinates) defined relative to some origin at a known location which may be defined, e.g., geographically, in civic terms, or by reference to a point, area, or volume, e.g., indicated on a map, floor plan, or building plan. In the description contained herein, the use of the term location may comprise any of these variants unless indicated otherwise. When computing the location of a UE, it is common to solve for local x, y, and possibly z coordinates and then, if desired, convert the local coordinates into absolute coordinates (e.g., for latitude, longitude, and altitude above or below mean sea level). 
     The UE  105  may be configured to communicate with other entities using one or more of a variety of technologies. The UE  105  may be configured to connect indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. The D2D P2P links may be supported with any appropriate D2D radio access technology (RAT), such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on. One or more of a group of UEs utilizing D2D communications may be within a geographic coverage area of a Transmission/Reception Point (TRP) such as one or more of the gNBs  110   a ,  110   b , and/or the ng-eNB  114 . Other UEs in such a group may be outside such geographic coverage areas, or may be otherwise unable to receive transmissions from a base station. Groups of UEs communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE may transmit to other UEs in the group. A TRP may facilitate scheduling of resources for D2D communications. In other cases, D2D communications may be carried out between UEs without the involvement of a TRP. One or more of a group of UEs utilizing D2D communications may be within a geographic coverage area of a TRP. Other UEs in such a group may be outside such geographic coverage areas, or be otherwise unable to receive transmissions from a base station. Groups of UEs communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE may transmit to other UEs in the group. A TRP may facilitate scheduling of resources for D2D communications. In other cases, D2D communications may be carried out between UEs without the involvement of a TRP. 
     Base stations (BSs) in the NG-RAN  135  shown in  FIG. 1  include NR Node Bs, referred to as the gNBs  110   a  and  110   b . Pairs of the gNBs  110   a ,  110   b  in the NG-RAN  135  may be connected to one another via one or more other gNBs. Access to the 5G network is provided to the UE  105  via wireless communication between the UE  105  and one or more of the gNBs  110   a ,  110   b , which may provide wireless communications access to the 5GC  140  on behalf of the UE  105  using 5G. In  FIG. 1 , the serving gNB for the UE  105  is assumed to be the gNB  110   a , although another gNB (e.g. the gNB  110   b ) may act as a serving gNB if the UE  105  moves to another location or may act as a secondary gNB to provide additional throughput and bandwidth to the UE  105 . 
     Base stations (BSs) in the NG-RAN  135  shown in  FIG. 1  may include the ng-eNB  114 , also referred to as a next generation evolved Node B. The ng-eNB  114  may be connected to one or more of the gNBs  110   a ,  110   b  in the NG-RAN  135 , possibly via one or more other gNBs and/or one or more other ng-eNBs. The ng-eNB  114  may provide LTE wireless access and/or evolved LTE (eLTE) wireless access to the UE  105 . One or more of the gNBs  110   a ,  110   b  and/or the ng-eNB  114  may be configured to function as positioning-only beacons which may transmit signals to assist with determining the position of the UE  105  but may not receive signals from the UE  105  or from other UEs. 
     The BSs  110   a ,  110   b ,  114  may each comprise one or more TRPs. For example, each sector within a cell of a BS may comprise a TRP, although multiple TRPs may share one or more components (e.g., share a processor but have separate antennas). The system  100  may include only macro TRPs or the system  100  may have TRPs of different types, e.g., macro, pico, and/or femto TRPs, etc. A macro TRP may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by terminals with service subscription. A pico TRP may cover a relatively small geographic area (e.g., a pico cell) and may allow unrestricted access by terminals with service subscription. A femto or home TRP may cover a relatively small geographic area (e.g., a femto cell) and may allow restricted access by terminals having association with the femto cell (e.g., terminals for users in a home). 
     As noted, while  FIG. 1  depicts nodes configured to communicate according to 5G communication protocols, nodes configured to communicate according to other communication protocols, such as, for example, an LTE protocol or IEEE 802.11x protocol, may be used. For example, in an Evolved Packet System (EPS) providing LTE wireless access to the UE  105 , a RAN may comprise an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) which may comprise base stations comprising evolved Node Bs (eNBs). A core network for EPS may comprise an Evolved Packet Core (EPC). An EPS may comprise an E-UTRAN plus EPC, where the E-UTRAN corresponds to the NG-RAN  135  and the EPC corresponds to the 5GC  140  in  FIG. 1 . 
     The gNBs  110   a ,  110   b  and the ng-eNB  114  may communicate with the AMF  115 , which, for positioning functionality, communicates with the LMF  120 . The AMF  115  may support mobility of the UE  105 , including cell change and handover and may participate in supporting a signaling connection to the UE  105  and possibly data and voice bearers for the UE  105 . The LMF  120  may communicate directly with the UE  105 , e.g., through wireless communications, or directly with the BSs  110   a ,  110   b ,  114 . The LMF  120  may support positioning of the UE  105  when the UE  105  accesses the NG-RAN  135  and may support position procedures/methods such as Assisted GNSS (A-GNSS), Observed Time Difference of Arrival (OTDOA) (e.g., Downlink (DL) OTDOA or Uplink (UL) OTDOA), Round Trip Time (RTT), Multi-Cell RTT, Real Time Kinematics (RTK), Precise Point Positioning (PPP), Differential GNSS (DGNSS), Enhanced Cell ID (E-CID), angle of arrival (AoA), angle of departure (AoD), and/or other position methods. The LMF  120  may process location services requests for the UE  105 , e.g., received from the AMF  115  or from the GMLC  125 . The LMF  120  may be connected to the AMF  115  and/or to the GMLC  125 . The LMF  120  may be referred to by other names such as a Location Manager (LM), Location Function (LF), commercial LMF (CLMF), or value added LMF (VLMF). A node/system that implements the LMF  120  may additionally or alternatively implement other types of location-support modules, such as an Enhanced Serving Mobile Location Center (E-SMLC) or a Secure User Plane Location (SUPL) Location Platform (SLP). At least part of the positioning functionality (including derivation of the location of the UE  105 ) may be performed at the UE  105  (e.g., using signal measurements obtained by the UE  105  for signals transmitted by wireless nodes such as the gNBs  110   a ,  110   b  and/or the ng-eNB  114 , and/or assistance data provided to the UE  105 , e.g. by the LMF  120 ). The AMF  115  may serve as a control node that processes signaling between the UE  105  and the core network  140 , and may provide QoS (Quality of Service) flow and session management. The AMF  115  may support mobility of the UE  105  including cell change and handover and may participate in supporting signaling connection to the UE  105 . 
     The GMLC  125  may support a location request for the UE  105  received from the external client  130  and may forward such a location request to the AMF  115  for forwarding by the AMF  115  to the LMF  120  or may forward the location request directly to the LMF  120 . A location response from the LMF  120  (e.g., containing a location estimate for the UE  105 ) may be returned to the GMLC  125  either directly or via the AMF  115  and the GMLC  125  may then return the location response (e.g., containing the location estimate) to the external client  130 . The GMLC  125  is shown connected to both the AMF  115  and LMF  120 , though only one of these connections may be supported by the 5GC  140  in some implementations. 
     As further illustrated in  FIG. 1 , the LMF  120  may communicate with the gNBs  110   a ,  110   b  and/or the ng-eNB  114  using a New Radio Position Protocol A (which may be referred to as NPPa or NRPPa), which may be defined in 3GPP Technical Specification (TS)  38 . 455 . NRPPa may be the same as, similar to, or an extension of the LTE Positioning Protocol A (LPPa) defined in 3GPP TS 36.455, with NRPPa messages being transferred between the gNB  110   a  (or the gNB  110   b ) and the LMF  120 , and/or between the ng-eNB  114  and the LMF  120 , via the AMF  115 . As further illustrated in  FIG. 1 , the LMF  120  and the UE  105  may communicate using an LTE Positioning Protocol (LPP), which may be defined in 3GPP TS 36.355. The LMF  120  and the UE  105  may also or instead communicate using a New Radio Positioning Protocol (which may be referred to as NPP or NRPP), which may be the same as, similar to, or an extension of LPP. Here, LPP and/or NPP messages may be transferred between the UE  105  and the LMF  120  via the AMF  115  and the serving gNB  110   a ,  110   b  or the serving ng-eNB  114  for the UE  105 . For example, LPP and/or NPP messages may be transferred between the LMF  120  and the AMF  115  using a 5G Location Services Application Protocol (LCS AP) and may be transferred between the AMF  115  and the UE  105  using a 5G Non-Access Stratum (NAS) protocol. The LPP and/or NPP protocol may be used to support positioning of the UE  105  using UE-assisted and/or UE-based position methods such as A-GNSS, RTK, OTDOA and/or E-CID. The NRPPa protocol may be used to support positioning of the UE  105  using network-based position methods such as E-CID (e.g., when used with measurements obtained by the gNB  110   a ,  110   b  or the ng-eNB  114 ) and/or may be used by the LMF  120  to obtain location related information from the gNBs  110   a ,  110   b  and/or the ng-eNB  114 , such as parameters defining directional SS transmissions from the gNBs  110   a ,  110   b , and/or the ng-eNB  114 . The LMF  120  may be co-located or integrated with a gNB or a TRP, or may be disposed remote from the gNB and/or the TRP and configured to communicate directly or indirectly with the gNB and/or the TRP. 
     With a UE-assisted position method, the UE  105  may obtain location measurements and send the measurements to a location server (e.g., the LMF  120 ) for computation of a location estimate for the UE  105 . For example, the location measurements may include one or more of a Received Signal Strength Indication (RSSI), Round Trip signal propagation Time (RTT), Reference Signal Time Difference (RSTD), Reference Signal Received Power (RSRP) and/or Reference Signal Received Quality (RSRQ) for the gNBs  110   a ,  110   b , the ng-eNB  114 , and/or a WLAN AP. The location measurements may also or instead include measurements of GNSS pseudorange, code phase, and/or carrier phase for the SVs  190 - 193 . 
     With a UE-based position method, the UE  105  may obtain location measurements (e.g., which may be the same as or similar to location measurements for a UE-assisted position method) and may compute a location of the UE  105  (e.g., with the help of assistance data received from a location server such as the LMF  120  or broadcast by the gNBs  110   a ,  110   b , the ng-eNB  114 , or other base stations or APs). 
     With a network-based position method, one or more base stations (e.g., the gNBs  110   a ,  110   b , and/or the ng-eNB  114 ) or APs may obtain location measurements (e.g., measurements of RSSI, RTT, RSRP, RSRQ or Time Of Arrival (ToA) for signals transmitted by the UE  105 ) and/or may receive measurements obtained by the UE  105 . The one or more base stations or APs may send the measurements to a location server (e.g., the LMF  120 ) for computation of a location estimate for the UE  105 . 
     Information provided by the gNBs  110   a ,  110   b , and/or the ng-eNB  114  to the LMF  120  using NRPPa may include timing and configuration information for directional SS transmissions and location coordinates. The LMF  120  may provide some or all of this information to the UE  105  as assistance data in an LPP and/or NPP message via the NG-RAN  135  and the 5GC  140 . 
     An LPP or NPP message sent from the LMF  120  to the UE  105  may instruct the UE  105  to do any of a variety of things depending on desired functionality. For example, the LPP or NPP message could contain an instruction for the UE  105  to obtain measurements for GNSS (or A-GNSS), WLAN, E-CID, and/or OTDOA (or some other position method). In the case of E-CID, the LPP or NPP message may instruct the UE  105  to obtain one or more measurement quantities (e.g., beam ID, beam width, mean angle, RSRP, RSRQ measurements) of directional signals transmitted within particular cells supported by one or more of the gNBs  110   a ,  110   b , and/or the ng-eNB  114  (or supported by some other type of base station such as an eNB or WiFi AP). The UE  105  may send the measurement quantities back to the LMF  120  in an LPP or NPP message (e.g., inside a 5G NAS message) via the serving gNB  110   a  (or the serving ng-eNB  114 ) and the AMF  115 . 
     As noted, while the communication system  100  is described in relation to 5G technology, the communication system  100  may be implemented to support other communication technologies, such as GSM, WCDMA, LTE, etc., that are used for supporting and interacting with mobile devices such as the UE  105  (e.g., to implement voice, data, positioning, and other functionalities). In some such embodiments, the 5GC  140  may be configured to control different air interfaces. For example, the 5GC  140  may be connected to a WLAN using a Non-3GPP InterWorking Function (N3IWF, not shown  FIG. 1 ) in the 5GC  150 . For example, the WLAN may support IEEE 802.11 WiFi access for the UE  105  and may comprise one or more WiFi APs. Here, the N3IWF may connect to the WLAN and to other elements in the 5GC  140  such as the AMF  115 . In some embodiments, both the NG-RAN  135  and the 5GC  140  may be replaced by one or more other RANs and one or more other core networks. For example, in an EPS, the NG-RAN  135  may be replaced by an E-UTRAN containing eNBs and the 5GC  140  may be replaced by an EPC containing a Mobility Management Entity (MME) in place of the AMF  115 , an E-SMLC in place of the LMF  120 , and a GMLC that may be similar to the GMLC  125 . In such an EPS, the E-SMLC may use LPPa in place of NRPPa to send and receive location information to and from the eNBs in the E-UTRAN and may use LPP to support positioning of the UE  105 . In these other embodiments, positioning of the UE  105  using directional PRSs may be supported in an analogous manner to that described herein for a 5G network with the difference that functions and procedures described herein for the gNBs  110   a ,  110   b , the ng-eNB  114 , the AMF  115 , and the LMF  120  may, in some cases, apply instead to other network elements such eNBs, WiFi APs, an MME, and an E-SMLC. 
     As noted, in some embodiments, positioning functionality may be implemented, at least in part, using the directional SS beams, sent by base stations (such as the gNBs  110   a ,  110   b , and/or the ng-eNB  114 ) that are within range of the UE whose position is to be determined (e.g., the UE  105  of  FIG. 1 ). The UE may, in some instances, use the directional SS beams from a plurality of base stations (such as the gNBs  110   a ,  110   b , the ng-eNB  114 , etc.) to compute the UE&#39;s position. 
     Referring also to  FIG. 2 , a UE  200  is an example of one of the UEs  105 ,  106  and comprises a computing platform including a processor  210 , memory  211  including software (SW)  212 , one or more sensors  213 , a transceiver interface  214  for a transceiver  215  (that includes a wireless transceiver  240  and a wired transceiver  250 ), a user interface  216 , a Satellite Positioning System (SPS) receiver  217 , a camera  218 , and a position device (PD)  219 . The processor  210 , the memory  211 , the sensor(s)  213 , the transceiver interface  214 , the user interface  216 , the SPS receiver  217 , the camera  218 , and the position device  219  may be communicatively coupled to each other by a bus  220  (which may be configured, e.g., for optical and/or electrical communication). One or more of the shown apparatus (e.g., the camera  218 , the position device  219 , and/or one or more of the sensor(s)  213 , etc.) may be omitted from the UE  200 . The processor  210  may include one or more intelligent hardware devices, e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc. The processor  210  may comprise multiple processors including a general-purpose/application processor  230 , a Digital Signal Processor (DSP)  231 , a modem processor  232 , a video processor  233 , and/or a sensor processor  234 . One or more of the processors  230 - 234  may comprise multiple devices (e.g., multiple processors). For example, the sensor processor  234  may comprise, e.g., processors for radar, ultrasound, and/or lidar, etc. The modem processor  232  may support dual SIM/dual connectivity (or even more SIMs). For example, a SIM (Subscriber Identity Module or Subscriber Identification Module) may be used by an Original Equipment Manufacturer (OEM), and another SIM may be used by an end user of the UE  200  for connectivity. The memory  211  is a non-transitory storage medium that may include random access memory (RAM), flash memory, disc memory, and/or read-only memory (ROM), etc. The memory  211  stores the software  212  which may be processor-readable, processor-executable software code containing instructions that are configured to, when executed, cause the processor  210  to perform various functions described herein. Alternatively, the software  212  may not be directly executable by the processor  210  but may be configured to cause the processor  210 , e.g., when compiled and executed, to perform the functions. The description may refer only to the processor  210  performing a function, but this includes other implementations such as where the processor  210  executes software and/or firmware. The description may refer to the processor  210  performing a function as shorthand for one or more of the processors  230 - 234  performing the function. The description may refer to the UE  200  performing a function as shorthand for one or more appropriate components of the UE  200  performing the function. The processor  210  may include a memory with stored instructions in addition to and/or instead of the memory  211 . Functionality of the processor  210  is discussed more fully below. 
     The configuration of the UE  200  shown in  FIG. 2  is an example and not limiting of the disclosure, including the claims, and other configurations may be used. For example, an example configuration of the UE includes one or more of the processors  230 - 234  of the processor  210 , the memory  211 , and the wireless transceiver  240 . Other example configurations include one or more of the processors  230 - 234  of the processor  210 , the memory  211 , the wireless transceiver  240 , and one or more of the sensor(s)  213 , the user interface  216 , the SPS receiver  217 , the camera  218 , the PD  219 , and/or the wired transceiver  250 . 
     The UE  200  may comprise the modem processor  232  that may be capable of performing baseband processing of signals received and down-converted by the transceiver  215  and/or the SPS receiver  217 . The modem processor  232  may perform baseband processing of signals to be upconverted for transmission by the transceiver  215 . Also or alternatively, baseband processing may be performed by the processor  230  and/or the DSP  231 . Other configurations, however, may be used to perform baseband processing. 
     The UE  200  may include the sensor(s)  213  that may include, for example, one or more of various types of sensors such as one or more inertial sensors, one or more magnetometers, one or more environment sensors, one or more optical sensors, one or more weight sensors, and/or one or more radio frequency (RF) sensors, etc. The sensor(s)  213  may include a radar system, a lidar system, and/or a sonar system, including one or more antennas as appropriate. An inertial measurement unit (IMU) may comprise, for example, one or more accelerometers (e.g., collectively responding to acceleration of the UE  200  in three dimensions) and/or one or more gyroscopes (e.g., three-dimensional gyroscope(s)). The sensor(s)  213  may include one or more magnetometers (e.g., three-dimensional magnetometer(s)) to determine orientation (e.g., relative to magnetic north and/or true north) that may be used for any of a variety of purposes, e.g., to support one or more compass applications. The environment sensor(s) may comprise, for example, one or more temperature sensors, one or more barometric pressure sensors, one or more ambient light sensors, one or more camera imagers, and/or one or more microphones, etc. The sensor(s)  213  may generate analog and/or digital signals indications of which may be stored in the memory  211  and processed by the DSP  231  and/or the processor  230  in support of one or more applications such as, for example, applications directed to positioning and/or navigation operations. 
     The sensor(s)  213  may be used in relative location measurements, relative location determination, motion determination, etc. Information detected by the sensor(s)  213  may be used for motion detection, relative displacement, dead reckoning, sensor-based location determination, and/or sensor-assisted location determination. The sensor(s)  213  may be useful to determine whether the UE  200  is fixed (stationary) or mobile and/or whether to report certain useful information to the LMF  120  regarding the mobility of the UE  200 . For example, based on the information obtained/measured by the sensor(s)  213 , the UE  200  may notify/report to the LMF  120  that the UE  200  has detected movements or that the UE  200  has moved, and report the relative displacement/distance (e.g., via dead reckoning, or sensor-based location determination, or sensor-assisted location determination enabled by the sensor(s)  213 ). In another example, for relative positioning information, the sensors/IMU can be used to determine the angle and/or orientation of the other device with respect to the UE  200 , etc. 
     The IMU may be configured to provide measurements about a direction of motion and/or a speed of motion of the UE  200 , which may be used in relative location determination. For example, one or more accelerometers and/or one or more gyroscopes of the IMU may detect, respectively, a linear acceleration and a speed of rotation of the UE  200 . The linear acceleration and speed of rotation measurements of the UE  200  may be integrated over time to determine an instantaneous direction of motion as well as a displacement of the UE  200 . The instantaneous direction of motion and the displacement may be integrated to track a location of the UE  200 . For example, a reference location of the UE  200  may be determined, e.g., using the SPS receiver  217  (and/or by some other means) for a moment in time and measurements from the accelerometer(s) and gyroscope(s) taken after this moment in time may be used in dead reckoning to determine present location of the UE  200  based on movement (direction and distance) of the UE  200  relative to the reference location. 
     The magnetometer(s) may determine magnetic field strengths in different directions which may be used to determine orientation of the UE  200 . For example, the orientation may be used to provide a digital compass for the UE  200 . The magnetometer(s) may include a two-dimensional magnetometer configured to detect and provide indications of magnetic field strength in two orthogonal dimensions. Alternatively, the magnetometer(s) may include a three-dimensional magnetometer configured to detect and provide indications of magnetic field strength in three orthogonal dimensions. The magnetometer(s) may provide means for sensing a magnetic field and providing indications of the magnetic field, e.g., to the processor  210 . 
     The transceiver  215  may include a wireless transceiver  240  and a wired transceiver  250  configured to communicate with other devices through wireless connections and wired connections, respectively. For example, the wireless transceiver  240  may include a wireless transmitter  242  and a wireless receiver  244  coupled to one or more antennas  246  for transmitting (e.g., on one or more uplink channels and/or one or more sidelink channels) and/or receiving (e.g., on one or more downlink channels and/or one or more sidelink channels) wireless signals  248  and transducing signals from the wireless signals  248  to wired (e.g., electrical and/or optical) signals and from wired (e.g., electrical and/or optical) signals to the wireless signals  248 . Thus, the wireless transmitter  242  may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wireless receiver  244  may include multiple receivers that may be discrete components or combined/integrated components. While a single antenna  246  is shown in  FIG. 2 , the antenna  246  may include more than one antenna, e.g., for diversity and/or to provide a phased array of antennas (although a single antenna may be a phased-array antenna). The wireless transceiver  240  may be configured to communicate signals (e.g., with TRPs and/or one or more other devices) according to a variety of radio access technologies (RATs) such as 5G New Radio (NR), GSM (Global System for Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbee etc. New Radio may use mm-wave frequencies and/or sub-6 GHz frequencies. The wired transceiver  250  may include a wired transmitter  252  and a wired receiver  254  configured for wired communication, e.g., with the network  135 . The wired transmitter  252  may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wired receiver  254  may include multiple receivers that may be discrete components or combined/integrated components. The wired transceiver  250  may be configured, e.g., for optical communication and/or electrical communication. The transceiver  215  may be communicatively coupled to the transceiver interface  214 , e.g., by optical and/or electrical connection. The transceiver interface  214  may be at least partially integrated with the transceiver  215 . 
     The user interface  216  may comprise one or more of several devices such as, for example, a speaker, microphone, display device, vibration device, keyboard, touch screen, etc. The user interface  216  may include more than one of any of these devices. The user interface  216  may be configured to enable a user to interact with one or more applications hosted by the UE  200 . For example, the user interface  216  may store indications of analog and/or digital signals in the memory  211  to be processed by DSP  231  and/or the general-purpose processor  230  in response to action from a user. Similarly, applications hosted on the UE  200  may store indications of analog and/or digital signals in the memory  211  to present an output signal to a user. The user interface  216  may include an audio input/output (I/O) device comprising, for example, a speaker, a microphone, digital-to-analog circuitry, analog-to-digital circuitry, an amplifier and/or gain control circuitry (including more than one of any of these devices). Other configurations of an audio I/O device may be used. Also or alternatively, the user interface  216  may comprise one or more touch sensors responsive to touching and/or pressure, e.g., on a keyboard and/or touch screen of the user interface  216 . 
     The SPS receiver  217  (e.g., a Global Positioning System (GPS) receiver) may be capable of receiving and acquiring SPS signals  260  via an SPS antenna  262 . The antenna  262  is configured to transduce the wireless signals  260  to wired signals, e.g., electrical or optical signals, and may be integrated with the antenna  246 . The SPS receiver  217  may be configured to process, in whole or in part, the acquired SPS signals  260  for estimating a location of the UE  200 . For example, the SPS receiver  217  may be configured to determine location of the UE  200  by trilateration using the SPS signals  260 . The general-purpose processor  230 , the memory  211 , the DSP  231  and/or one or more specialized processors (not shown) may be utilized to process acquired SPS signals, in whole or in part, and/or to calculate an estimated location of the UE  200 , in conjunction with the SPS receiver  217 . The memory  211  may store indications (e.g., measurements) of the SPS signals  260  and/or other signals (e.g., signals acquired from the wireless transceiver  240 ) for use in performing positioning operations. The general-purpose processor  230 , the DSP  231 , and/or one or more specialized processors, and/or the memory  211  may provide or support a location engine for use in processing measurements to estimate a location of the UE  200 . 
     The UE  200  may include the camera  218  for capturing still or moving imagery. The camera  218  may comprise, for example, an imaging sensor (e.g., a charge coupled device or a CMOS imager), a lens, analog-to-digital circuitry, frame buffers, etc. Additional processing, conditioning, encoding, and/or compression of signals representing captured images may be performed by the general-purpose processor  230  and/or the DSP  231 . Also or alternatively, the video processor  233  may perform conditioning, encoding, compression, and/or manipulation of signals representing captured images. The video processor  233  may decode/decompress stored image data for presentation on a display device (not shown), e.g., of the user interface  216 . 
     The position device (PD)  219  may be configured to determine a position of the UE  200 , motion of the UE  200 , and/or relative position of the UE  200 , and/or time. For example, the PD  219  may communicate with, and/or include some or all of, the SPS receiver  217 . The PD  219  may work in conjunction with the processor  210  and the memory  211  as appropriate to perform at least a portion of one or more positioning methods, although the description herein may refer only to the PD  219  being configured to perform, or performing, in accordance with the positioning method(s). The PD  219  may also or alternatively be configured to determine location of the UE  200  using terrestrial-based signals (e.g., at least some of the signals  248 ) for trilateration, for assistance with obtaining and using the SPS signals  260 , or both. The PD  219  may be configured to use one or more other techniques (e.g., relying on the UE&#39;s self-reported location (e.g., part of the UE&#39;s position beacon)) for determining the location of the UE  200 , and may use a combination of techniques (e.g., SPS and terrestrial positioning signals) to determine the location of the UE  200 . The PD  219  may include one or more of the sensors  213  (e.g., gyroscope(s), accelerometer(s), magnetometer(s), etc.) that may sense orientation and/or motion of the UE  200  and provide indications thereof that the processor  210  (e.g., the processor  230  and/or the DSP  231 ) may be configured to use to determine motion (e.g., a velocity vector and/or an acceleration vector) of the UE  200 . The PD  219  may be configured to provide indications of uncertainty and/or error in the determined position and/or motion. Functionality of the PD  219  may be provided in a variety of manners and/or configurations, e.g., by the general purpose/application processor  230 , the transceiver  215 , the SPS receiver  262 , and/or another component of the UE  200 , and may be provided by hardware, software, firmware, or various combinations thereof. 
     Referring also to  FIG. 3 , an example of a TRP  300  of the BSs  110   a ,  110   b ,  114  comprises a computing platform including a processor  310 , memory  311  including software (SW)  312 , and a transceiver  315 . The processor  310 , the memory  311 , and the transceiver  315  may be communicatively coupled to each other by a bus  320  (which may be configured, e.g., for optical and/or electrical communication). One or more of the shown apparatus (e.g., a wireless interface) may be omitted from the TRP  300 . The processor  310  may include one or more intelligent hardware devices, e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc. The processor  310  may comprise multiple processors (e.g., including a general-purpose/application processor, a DSP, a modem processor, a video processor, and/or a sensor processor as shown in  FIG. 2 ). The memory  311  is a non-transitory storage medium that may include random access memory (RAM)), flash memory, disc memory, and/or read-only memory (ROM), etc. The memory  311  stores the software  312  which may be processor-readable, processor-executable software code containing instructions that are configured to, when executed, cause the processor  310  to perform various functions described herein. Alternatively, the software  312  may not be directly executable by the processor  310  but may be configured to cause the processor  310 , e.g., when compiled and executed, to perform the functions. 
     The description may refer only to the processor  310  performing a function, but this includes other implementations such as where the processor  310  executes software and/or firmware. The description may refer to the processor  310  performing a function as shorthand for one or more of the processors contained in the processor  310  performing the function. The description may refer to the TRP  300  performing a function as shorthand for one or more appropriate components (e.g., the processor  310  and the memory  311 ) of the TRP  300  (and thus of one of the BSs  110   a ,  110   b ,  114 ) performing the function. The processor  310  may include a memory with stored instructions in addition to and/or instead of the memory  311 . Functionality of the processor  310  is discussed more fully below. 
     The transceiver  315  may include a wireless transceiver  340  and/or a wired transceiver  350  configured to communicate with other devices through wireless connections and wired connections, respectively. For example, the wireless transceiver  340  may include a wireless transmitter  342  and a wireless receiver  344  coupled to one or more antennas  346  for transmitting (e.g., on one or more uplink channels and/or one or more downlink channels) and/or receiving (e.g., on one or more downlink channels and/or one or more uplink channels) wireless signals  348  and transducing signals from the wireless signals  348  to wired (e.g., electrical and/or optical) signals and from wired (e.g., electrical and/or optical) signals to the wireless signals  348 . Thus, the wireless transmitter  342  may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wireless receiver  344  may include multiple receivers that may be discrete components or combined/integrated components. While a single antenna  346  is shown in  FIG. 3 , the antenna  346  may include more than one antenna, e.g., for diversity and/or to provide a phased array of antennas (although a single antenna may be a phased-array antenna). The wireless transceiver  340  may be configured to communicate signals (e.g., with the UE  200 , one or more other UEs, and/or one or more other devices) according to a variety of radio access technologies (RATs) such as 5G New Radio (NR), GSM (Global System for Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbee etc. The wired transceiver  350  may include a wired transmitter  352  and a wired receiver  354  configured for wired communication, e.g., a network interface that may be utilized to communicate with the network  135  to send communications to, and receive communications from, the LMF  120 , for example, and/or one or more other network entities. The wired transmitter  352  may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wired receiver  354  may include multiple receivers that may be discrete components or combined/integrated components. The wired transceiver  350  may be configured, e.g., for optical communication and/or electrical communication. 
     The configuration of the TRP  300  shown in  FIG. 3  is an example and not limiting of the disclosure, including the claims, and other configurations may be used. For example, the description herein discusses that the TRP  300  is configured to perform or performs several functions, but one or more of these functions may be performed by the LMF  120  and/or the UE  200  (i.e., the LMF  120  and/or the UE  200  may be configured to perform one or more of these functions). 
     Referring also to  FIG. 4 , a server  400 , which is an example of the LMF  120 , comprises a computing platform including a processor  410 , memory  411  including software (SW)  412 , and a transceiver  415 . The processor  410 , the memory  411 , and the transceiver  415  may be communicatively coupled to each other by a bus  420  (which may be configured, e.g., for optical and/or electrical communication). One or more of the shown apparatus (e.g., a wireless interface) may be omitted from the server  400 . The processor  410  may include one or more intelligent hardware devices, e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc. The processor  410  may comprise multiple processors (e.g., including a general-purpose/application processor, a DSP, a modem processor, a video processor, and/or a sensor processor as shown in  FIG. 2 ). The memory  411  is a non-transitory storage medium that may include random access memory (RAM)), flash memory, disc memory, and/or read-only memory (ROM), etc. The memory  411  stores the software  412  which may be processor-readable, processor-executable software code containing instructions that are configured to, when executed, cause the processor  410  to perform various functions described herein. Alternatively, the software  412  may not be directly executable by the processor  410  but may be configured to cause the processor  410 , e.g., when compiled and executed, to perform the functions. The description may refer only to the processor  410  performing a function, but this includes other implementations such as where the processor  410  executes software and/or firmware. The description may refer to the processor  410  performing a function as shorthand for one or more of the processors contained in the processor  410  performing the function. The description may refer to the server  400  performing a function as shorthand for one or more appropriate components of the server  400  performing the function. The processor  410  may include a memory with stored instructions in addition to and/or instead of the memory  411 . Functionality of the processor  410  is discussed more fully below. 
     The transceiver  415  may include a wireless transceiver  440  and/or a wired transceiver  450  configured to communicate with other devices through wireless connections and wired connections, respectively. For example, the wireless transceiver  440  may include a wireless transmitter  442  and a wireless receiver  444  coupled to one or more antennas  446  for transmitting (e.g., on one or more downlink channels) and/or receiving (e.g., on one or more uplink channels) wireless signals  448  and transducing signals from the wireless signals  448  to wired (e.g., electrical and/or optical) signals and from wired (e.g., electrical and/or optical) signals to the wireless signals  448 . Thus, the wireless transmitter  442  may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wireless receiver  444  may include multiple receivers that may be discrete components or combined/integrated components. The wireless transceiver  440  may be configured to communicate signals (e.g., with the UE  200 , one or more other UEs, and/or one or more other devices) according to a variety of radio access technologies (RATs) such as 5G New Radio (NR), GSM (Global System for Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbee etc. The wired transceiver  450  may include a wired transmitter  452  and a wired receiver  454  configured for wired communication, e.g., a network interface that may be utilized to communicate with the network  135  to send communications to, and receive communications from, the TRP  300 , for example, and/or one or more other entities. The wired transmitter  452  may include multiple transmitters that may be discrete components or combined/integrated components, and/or the wired receiver  454  may include multiple receivers that may be discrete components or combined/integrated components. The wired transceiver  450  may be configured, e.g., for optical communication and/or electrical communication. 
     The description herein may refer only to the processor  410  performing a function, but this includes other implementations such as where the processor  410  executes software (stored in the memory  411 ) and/or firmware. The description herein may refer to the server  400  performing a function as shorthand for one or more appropriate components (e.g., the processor  410  and the memory  411 ) of the server  400  performing the function. 
     Positioning Techniques 
     For terrestrial positioning of a UE in cellular networks, techniques such as Advanced Forward Link Trilateration (AFLT) and Observed Time Difference Of Arrival (OTDOA) often operate in “UE-assisted” mode in which measurements of reference signals (e.g., PRS, CRS, etc.) transmitted by base stations are taken by the UE and then provided to a location server. The location server then calculates the position of the UE based on the measurements and known locations of the base stations. Because these techniques use the location server to calculate the position of the UE, rather than the UE itself, these positioning techniques are not frequently used in applications such as car or cell-phone navigation, which instead typically rely on satellite-based positioning. 
     A UE may use a Satellite Positioning System (SPS) (a Global Navigation Satellite System (GNSS)) for high-accuracy positioning using precise point positioning (PPP) or real time kinematic (RTK) technology. These technologies use assistance data such as measurements from ground-based stations. LTE Release 15 allows the data to be encrypted so that only the UEs subscribed to the service can read the information. Such assistance data varies with time. Thus, a UE subscribed to the service may not easily “break encryption” for other UEs by passing on the data to other UEs that have not paid for the subscription. The passing on would need to be repeated every time the assistance data changes. 
     In UE-assisted positioning, the UE sends measurements (e.g., TDOA, Angle of Arrival (AoA), etc.) to the positioning server (e.g., LMF/eSMLC). The positioning server has the base station almanac (BSA) that contains multiple ‘entries’ or ‘records’, one record per cell, where each record contains geographical cell location but also may include other data. An identifier of the ‘record’ among the multiple ‘records’ in the BSA may be referenced. The BSA and the measurements from the UE may be used to compute the position of the UE. 
     In conventional UE-based positioning, a UE computes its own position, thus avoiding sending measurements to the network (e.g., location server), which in turn improves latency and scalability. The UE uses relevant BSA record information (e.g., locations of gNBs (more broadly base stations)) from the network. The BSA information may be encrypted. But since the BSA information varies much less often than, for example, the PPP or RTK assistance data described earlier, it may be easier to make the BSA information (compared to the PPP or RTK information) available to UEs that did not subscribe and pay for decryption keys. Transmissions of reference signals by the gNBs make BSA information potentially accessible to crowd-sourcing or war-driving, essentially enabling BSA information to be generated based on in-the-field and/or over-the-top observations. 
     Positioning techniques may be characterized and/or assessed based on one or more criteria such as position determination accuracy and/or latency. Latency is a time elapsed between an event that triggers determination of position-related data and the availability of that data at a positioning system interface, e.g., an interface of the LMF  120 . At initialization of a positioning system, the latency for the availability of position-related data is called time to first fix (TTFF), and is larger than latencies after the TTFF. An inverse of a time elapsed between two consecutive position-related data availabilities is called an update rate, i.e., the rate at which position-related data are generated after the first fix. Latency may depend on processing capability, e.g., of the UE. For example, a UE may report a processing capability of the UE as a duration of DL PRS symbols in units of time (e.g., milliseconds) that the UE can process every T amount of time (e.g., T ms) assuming 272 PRB (Physical Resource Block) allocation. Other examples of capabilities that may affect latency are a number of TRPs from which the UE can process PRS, a number of PRS that the UE can process, and a bandwidth of the UE. 
     One or more of many different positioning techniques (also called positioning methods) may be used to determine position of an entity such as one of the UEs  105 ,  106 . For example, known position-determination techniques include RTT, multi-RTT, OTDOA (also called TDOA and including UL-TDOA and DL-TDOA), Enhanced Cell Identification (E-CID), DL-AoD, UL-AoA, etc. RTT uses a time for a signal to travel from one entity to another and back to determine a range between the two entities. The range, plus a known location of a first one of the entities and an angle between the two entities (e.g., an azimuth angle) can be used to determine a location of the second of the entities. In multi-RTT (also called multi-cell RTT), multiple ranges from one entity (e.g., a UE) to other entities (e.g., TRPs) and known locations of the other entities may be used to determine the location of the one entity. In TDOA techniques, the difference in travel times between one entity and other entities may be used to determine relative ranges from the other entities and those, combined with known locations of the other entities may be used to determine the location of the one entity. Angles of arrival and/or departure may be used to help determine location of an entity. For example, an angle of arrival or an angle of departure of a signal combined with a range between devices (determined using signal, e.g., a travel time of the signal, a received power of the signal, etc.) and a known location of one of the devices may be used to determine a location of the other device. The angle of arrival or departure may be an azimuth angle relative to a reference direction such as true north. The angle of arrival or departure may be a zenith angle relative to directly upward from an entity (i.e., relative to radially outward from a center of Earth). E-CID uses the identity of a serving cell, the timing advance (i.e., the difference between receive and transmit times at the UE), estimated timing and power of detected neighbor cell signals, and possibly angle of arrival (e.g., of a signal at the UE from the base station or vice versa) to determine location of the UE. In TDOA, the difference in arrival times at a receiving device of signals from different sources along with known locations of the sources and known offset of transmission times from the sources are used to determine the location of the receiving device. 
     In a network-centric RTT estimation, the serving base station instructs the UE to scan for/receive RTT measurement signals (e.g., PRS) on serving cells of two or more neighboring base stations (and typically the serving base station, as at least three base stations are needed). The one of more base stations transmit RTT measurement signals on low reuse resources (e.g., resources used by the base station to transmit system information) allocated by the network (e.g., a location server such as the LMF  120 ). The UE records the arrival time (also referred to as a receive time, a reception time, a time of reception, or a time of arrival (ToA)) of each RTT measurement signal relative to the UE&#39;s current downlink timing (e.g., as derived by the UE from a DL signal received from its serving base station), and transmits a common or individual RTT response message (e.g., SRS (sounding reference signal) for positioning, i.e., UL-PRS) to the one or more base stations (e.g., when instructed by its serving base station) and may include the time difference T Rx→Tx  (i.e., UE T Rx-Tx  or UE Rx-Tx ) between the ToA of the RTT measurement signal and the transmission time of the RTT response message in a payload of each RTT response message. The RTT response message would include a reference signal from which the base station can deduce the ToA of the RTT response. By comparing the difference T Tx→Rx  between the transmission time of the RTT measurement signal from the base station and the ToA of the RTT response at the base station to the UE-reported time difference T Rx→Tx , the base station can deduce the propagation time between the base station and the UE, from which the base station can determine the distance between the UE and the base station by assuming the speed of light during this propagation time. 
     A UE-centric RTT estimation is similar to the network-based method, except that the UE transmits uplink RTT measurement signal(s) (e.g., when instructed by a serving base station), which are received by multiple base stations in the neighborhood of the UE. Each involved base station responds with a downlink RTT response message, which may include the time difference between the ToA of the RTT measurement signal at the base station and the transmission time of the RTT response message from the base station in the RTT response message payload. 
     For both network-centric and UE-centric procedures, the side (network or UE) that performs the RTT calculation typically (though not always) transmits the first message(s) or signal(s) (e.g., RTT measurement signal(s)), while the other side responds with one or more RTT response message(s) or signal(s) that may include the difference between the ToA of the first message(s) or signal(s) and the transmission time of the RTT response message(s) or signal(s). 
     A multi-RTT technique may be used to determine position. For example, a first entity (e.g., a UE) may send out one or more signals (e.g., unicast, multicast, or broadcast from the base station) and multiple second entities (e.g., other TSPs such as base station(s) and/or UE(s)) may receive a signal from the first entity and respond to this received signal. The first entity receives the responses from the multiple second entities. The first entity (or another entity such as an LMF) may use the responses from the second entities to determine ranges to the second entities and may use the multiple ranges and known locations of the second entities to determine the location of the first entity by trilateration. 
     In some instances, additional information may be obtained in the form of an angle of arrival (AoA) or angle of departure (AoD) that defines a straight line direction (e.g., which may be in a horizontal plane or in three dimensions) or possibly a range of directions (e.g., for the UE from the locations of base stations). The intersection of two directions can provide another estimate of the location for the UE. 
     For positioning techniques using PRS (Positioning Reference Signal) signals (e.g., TDOA and RTT), PRS signals sent by multiple TRPs are measured and the arrival times of the signals, known transmission times, and known locations of the TRPs used to determine ranges from a UE to the TRPs. For example, an RSTD (Reference Signal Time Difference) may be determined for PRS signals received from multiple TRPs and used in a TDOA technique to determine position (location) of the UE. A positioning reference signal may be referred to as a PRS or a PRS signal. The PRS signals are typically sent using the same power and PRS signals with the same signal characteristics (e.g., same frequency shift) may interfere with each other such that a PRS signal from a more distant TRP may be overwhelmed by a PRS signal from a closer TRP such that the signal from the more distant TRP may not be detected. PRS muting may be used to help reduce interference by muting some PRS signals (reducing the power of the PRS signal, e.g., to zero and thus not transmitting the PRS signal). In this way, a weaker (at the UE) PRS signal may be more easily detected by the UE without a stronger PRS signal interfering with the weaker PRS signal. The term RS, and variations thereof (e.g., PRS, SRS), may refer to one reference signal or more than one reference signal. 
     Positioning reference signals (PRS) include downlink PRS (DL PRS) and uplink PRS (UL PRS) (which may be called SRS (Sounding Reference Signal) for positioning). PRS may comprise PRS resources or PRS resource sets of a frequency layer. A DL PRS positioning frequency layer (or simply a frequency layer) is a collection of DL PRS resource sets, from one or more TRPs, that have common parameters configured by higher-layer parameters DL-PRS-PositioningFrequencyLayer, DL-PRS-ResourceSet, and DL-PRS-Resource. Each frequency layer has a DL PRS subcarrier spacing (SCS) for the DL PRS resource sets and the DL PRS resources in the frequency layer. Each frequency layer has a DL PRS cyclic prefix (CP) for the DL PRS resource sets and the DL PRS resources in the frequency layer. In 5G, a resource block occupies 12 consecutive subcarriers and a specified number of symbols. Also, a DL PRS Point A parameter defines a frequency of a reference resource block (and the lowest subcarrier of the resource block), with DL PRS resources belonging to the same DL PRS resource set having the same Point A and all DL PRS resource sets belonging to the same frequency layer having the same Point A. A frequency layer also has the same DL PRS bandwidth, the same start PRB (and center frequency), and the same value of comb size (i.e., a frequency of PRS resource elements per symbol such that for comb-N, every N th  resource element is a PRS resource element). 
     A TRP may be configured, e.g., by instructions received from a server and/or by software in the TRP, to send DL PRS per a schedule. According to the schedule, the TRP may send the DL PRS intermittently, e.g., periodically at a consistent interval from an initial transmission. The TRP may be configured to send one or more PRS resource sets. A resource set is a collection of PRS resources across one TRP, with the resources having the same periodicity, a common muting pattern configuration (if any), and the same repetition factor across slots. Each of the PRS resource sets comprises multiple PRS resources, with each PRS resource comprising multiple Resource Elements (REs) that may be in multiple Resource Blocks (RBs) within N (one or more) consecutive symbol(s) within a slot. An RB is a collection of REs spanning a quantity of one or more consecutive symbols in the time domain and a quantity (12 for a 5G RB) of consecutive sub-carriers in the frequency domain. Each PRS resource is configured with an RE offset, slot offset, a symbol offset within a slot, and a number of consecutive symbols that the PRS resource may occupy within a slot. The RE offset defines the starting RE offset of the first symbol within a DL PRS resource in frequency. The relative RE offsets of the remaining symbols within a DL PRS resource are defined based on the initial offset. The slot offset is the starting slot of the DL PRS resource with respect to a corresponding resource set slot offset. The symbol offset determines the starting symbol of the DL PRS resource within the starting slot. Transmitted REs may repeat across slots, with each transmission being called a repetition such that there may be multiple repetitions in a PRS resource. The DL PRS resources in a DL PRS resource set are associated with the same TRP and each DL PRS resource has a DL PRS resource ID. A DL PRS resource ID in a DL PRS resource set is associated with a single beam transmitted from a single TRP (although a TRP may transmit one or more beams). 
     A PRS resource may also be defined by quasi-co-location and start PRB parameters. A quasi-co-location (QCL) parameter may define any quasi-co-location information of the DL PRS resource with other reference signals. The DL PRS may be configured to be QCL type D with a DL PRS or SS/PBCH (Synchronization Signal/Physical Broadcast Channel) Block from a serving cell or a non-serving cell. The DL PRS may be configured to be QCL type C with an SS/PBCH Block from a serving cell or a non-serving cell. The start PRB parameter defines the starting PRB index of the DL PRS resource with respect to reference Point A. The starting PRB index has a granularity of one PRB and may have a minimum value of 0 and a maximum value of 2176 PRBs. 
     A PRS resource set is a collection of PRS resources with the same periodicity, same muting pattern configuration (if any), and the same repetition factor across slots. Every time all repetitions of all PRS resources of the PRS resource set are configured to be transmitted is referred as an “instance”. Therefore, an “instance” of a PRS resource set is a specified number of repetitions for each PRS resource and a specified number of PRS resources within the PRS resource set such that once the specified number of repetitions are transmitted for each of the specified number of PRS resources, the instance is complete. An instance may also be referred to as an “occasion.” A DL PRS configuration including a DL PRS transmission schedule may be provided to a UE to facilitate (or even enable) the UE to measure the DL PRS. 
     Multiple frequency layers of PRS may be aggregated to provide an effective bandwidth that is larger than any of the bandwidths of the layers individually. Multiple frequency layers of component carriers (which may be consecutive and/or separate) and meeting criteria such as being quasi co-located (QCLed), and having the same antenna port, may be stitched to provide a larger effective PRS bandwidth (for DL PRS and UL PRS) resulting in increased time of arrival measurement accuracy. Being QCLed, the different frequency layers behave similarly, enabling stitching of the PRS to yield the larger effective bandwidth. The larger effective bandwidth, which may be referred to as the bandwidth of an aggregated PRS or the frequency bandwidth of an aggregated PRS, provides for better time-domain resolution (e.g., of TDOA). An aggregated PRS includes a collection of PRS resources and each PRS resource of an aggregated PRS may be called a PRS component, and each PRS component may be transmitted on different component carriers, bands, or frequency layers, or on different portions of the same band. 
     RTT positioning is an active positioning technique in that RTT uses positioning signals sent by TRPs to UEs and by UEs (that are participating in RTT positioning) to TRPs. The TRPs may send DL-PRS signals that are received by the UEs and the UEs may send SRS (Sounding Reference Signal) signals that are received by multiple TRPs. A sounding reference signal may be referred to as an SRS or an SRS signal. In 5G multi-RTT, coordinated positioning may be used with the UE sending a single UL-SRS for positioning that is received by multiple TRPs instead of sending a separate UL-SRS for positioning for each TRP. A TRP that participates in multi-RTT will typically search for UEs that are currently camped on that TRP (served UEs, with the TRP being a serving TRP) and also UEs that are camped on neighboring TRPs (neighbor UEs). Neighbor TRPs may be TRPs of a single BTS (e.g., gNB), or may be a TRP of one BTS and a TRP of a separate BTS. For RTT positioning, including multi-RTT positioning, the DL-PRS signal and the UL-SRS for positioning signal in a PRS/SRS for positioning signal pair used to determine RTT (and thus used to determine range between the UE and the TRP) may occur close in time to each other such that errors due to UE motion and/or UE clock drift and/or TRP clock drift are within acceptable limits. For example, signals in a PRS/SRS for positioning signal pair may be transmitted from the TRP and the UE, respectively, within about 10 ms of each other. With SRS for positioning signals being sent by UEs, and with PRS and SRS for positioning signals being conveyed close in time to each other, it has been found that radio-frequency (RF) signal congestion may result (which may cause excessive noise, etc.) especially if many UEs attempt positioning concurrently and/or that computational congestion may result at the TRPs that are trying to measure many UEs concurrently. 
     RTT positioning may be UE-based or UE-assisted. In UE-based RTT, the UE  200  determines the RTT and corresponding range to each of the TRPs  300  and the position of the UE  200  based on the ranges to the TRPs  300  and known locations of the TRPs  300 . In UE-assisted RTT, the UE  200  measures positioning signals and provides measurement information to the TRP  300 , and the TRP  300  determines the RTT and range. The TRP  300  provides ranges to a location server, e.g., the server  400 , and the server determines the location of the UE  200 , e.g., based on ranges to different TRPs  300 . The RTT and/or range may be determined by the TRP  300  that received the signal(s) from the UE  200 , by this TRP  300  in combination with one or more other devices, e.g., one or more other TRPs  300  and/or the server  400 , or by one or more devices other than the TRP  300  that received the signal(s) from the UE  200 . 
     Various positioning techniques are supported in 5G NR. The NR native positioning methods supported in 5G NR include DL-only positioning methods, UL-only positioning methods, and DL+UL positioning methods. Downlink-based positioning methods include DL-TDOA and DL-AoD. Uplink-based positioning methods include UL-TDOA and UL-AoA. Combined DL+UL-based positioning methods include RTT with one base station and RTT with multiple base stations (multi-RTT). 
     A position estimate (e.g., for a UE) may be referred to by other names, such as a location estimate, location, position, position fix, fix, or the like. A position estimate may be geodetic and comprise coordinates (e.g., latitude, longitude, and possibly altitude) or may be civic and comprise a street address, postal address, or some other verbal description of a location. A position estimate may further be defined relative to some other known location or defined in absolute terms (e.g., using latitude, longitude, and possibly altitude). A position estimate may include an expected error or uncertainty (e.g., by including an area or volume within which the location is expected to be included with some specified or default level of confidence). 
     Line-of-Sight/Non-Line-of-Sight Determination and Use 
     Various techniques may be implemented to determine whether a signal received by a target UE from another UE is a line-of-sight (LOS) transmission or a non-line-of-sight (NLOS) transmission, and thus whether the UE is LOS or NLOS with respect to the other UE. The target UE is the UE for which a location is to be determined and an anchor UE is a UE with a known location, even though the location may not be known at the time of signal exchange between the target UE and the anchor UE. The use of an NLOS signal between the anchor UE and the target UE to determine range between the target UE and the anchor UE may result in an incorrect (longer than actual) range being determined. If this incorrect range is used to determine the location of the target UE, then the determined location will likely be incorrect, and may be unacceptably incorrect (i.e., in error more than an acceptable threshold error). Situations arise where the target UE (e.g., a vehicle UE in a V2X context) is out of coverage of and the target UE uses anchor UEs to determine ranges between the target UE and the anchor UEs to determine location of the target UE. Determining whether a PRS from an anchor UE is LOS/NLOS without the help of infrastructure such as a gNB is useful to help ensure the accuracy of the determined location for the target UE. 
     Referring to  FIG. 5 , with further reference to  FIGS. 1-4 , a UE  500  includes a processor  510 , an interface  520 , a memory  530 , and a directional, reflection-based ranging system  540  communicatively coupled to each other by a bus  550 . The UE  500  may include the components shown in  FIG. 5 , and may include one or more other components such as any of those shown in  FIG. 2  such that the UE  200  may be an example of the UE  500 . For example, the processor  510  may include one or more of the components of the processor  210 . The interface  520  may include one or more of the components of the transceiver  215 . For example, the interface  520  includes a wireless transmitter  522 , a wireless receiver  524 , and an antenna  526 , e.g., corresponding to the wireless transmitter  242 , the wireless receiver  244 , and the antenna  246 . The interface  520  may include more than one antenna  526 , e.g., to facilitate electric beam steering of a communication beam, and/or the antenna(s)  526  may be configured with multiple elements configured (e.g., in combination with the wireless transmitter  522  and/or the wireless receiver  524 ) for electric beam steering. In this example, three antennas  526  are shown (with two of the antennas  526  being shown as being optional), but the UE  500  may be configured with other quantities of antennas. The processor  510  is configured to steer the antenna(s)  526  to point in different directions. For example, the processor  510  may electronically steer the antenna(s)  526  by controlling phases applied to signals transmitted by different elements of the antenna(s)  526 , and/or different ones of the antennas  526  (with more than one antenna  526  present), and controlling phases applied to signals received by different antenna elements of the antenna(s)  526 , and/or applied to different ones of the antennas  526 . The processor  510  may, for example, determine an AoA of a signal (e.g., a PRS) from another UE based on the direction of the beam of the antenna(s)  526  when the signal is received. Also or alternatively, the interface  520  may include the wired transmitter  252  and/or the wired receiver  254 . The memory  530  may be configured similarly to the memory  211 , e.g., including software with processor-readable instructions configured to cause the processor  510  to perform functions. 
     The ranging system  540  is configured to use reflections of transmitted signals to determine locations of objections in terms of angles to the objects relative to a coordinate system of the UE  500  and distances to the objects. The ranging system  540  includes a wireless transmitter  542 , a wireless receiver  544 , and an antenna  546  (which may comprise a single antenna element, multiple antenna elements, and/or multiple antennas). For example, separate antennas may be used for signal transmission and reflected signal reception, although the discussion herein refers to a single antenna. The ranging system  540  transmits signals from the wireless transmitter  542  via the antenna  546  and receives reflections of the transmitted signals by the wireless receiver  544  via the antenna  546 . The ranging system  540  may include a processor  548 , communicatively coupled to the wireless transmitter  542  and the wireless receiver  544  (and possibly to a memory, not shown). The processor  548  is configured to steer the antenna  546  to point in different directions. For example, the processor  548  may electronically steer the antenna  546  by controlling phases applied to signals transmitted by different elements of the antenna  546  and applied to signals received by different elements of the antenna  546 . The processor  548  may, for example, cause the antenna  546  to rotate a beam of the antenna  546 , e.g., at a constant angular rate. The ranging system  540  may be turned off during times that the UE  500  is not collecting information, e.g., measuring PRS, for use in determining the location of the UE  500 . The processor  548  may be configured to analyze time of departure of transmitted signals and time of arrival of reflected signals to determine distance from the UE  500  to an object, computing the distance between the UE  500  and the object as the difference in arrival and departure times divided by the speed of light. Also or alternatively, the processor  548  may be configured to determine the distance between the UE  500  and the object based on the transmitted signal power and the received signal power. The processor  548  is also configured to determine, for each determined distance, the direction of the object relative to the UE  500  based on the direction of the transmitted signal (e.g., as electronically steered by the processor  548 ). Some or all of the processor  548  may be disposed in the processor  510 , i.e., the processor  548  may not be physically separate from the processor  510 . 
     The ranging system  540  may take a variety of forms. For example, the ranging system may be a radar (radio detection and ranging) system, a lidar (light detection and ranging) system, a sonar (sound navigation and ranging) system, and/or or reflection-based ranging system. The ranging system  540  is directional in that a beamwidth produced by the antenna  526  is sufficiently narrow to enable the ranging system  540  to determine meaningful information regarding the directions of objects relative to the UE  500 . For example, the antenna  526  may have a beamwidth of about 1°-2° and the ranging system  540  may provide directions to objects relative to the UE  500  with about +/−0.2° of error. These values of beamwidth and angular error are examples only, and ranging systems with other beamwidths and/or errors may be used. 
     The description herein may refer only to the processor  510  performing a function, but this includes other implementations such as where the processor  510  executes software (stored in the memory  530 ) and/or firmware. The description herein may refer to the UE  500  performing a function as shorthand for one or more appropriate components (e.g., the processor  510  and the memory  530 ) of the UE  500  performing the function. The processor  510  (possibly in conjunction with the memory  530  and, as appropriate, the interface  520 ) includes an LOS/NLOS unit  550  (line-of-sight/non-line-of-sight unit). The LOS/NLOS unit  550  is configured to determine whether another UE is within a line of sight of the UE  500  or is in a non-line-of-sight relationship relative to the UE  500  (e.g., a line of sight between the UE  500  and the other UE is blocked or obscured). The LOS/NLOS unit  550  is configured to determine whether an angle between the UE  500  and the other UE determined by the ranging system  540  corresponds to (e.g., is within an angular threshold difference of) an angle determined from reception of one or more communication signals and, for angles that correspond, to determine whether the distances corresponding to the ranging and communication signals correspond (e.g., are within a distance threshold difference). The LOS/NLOS unit  550  is configured to conclude that an LOS condition exists between the UE  500  and another UE based on the distances corresponding and to conclude that the other UE is NLOS with respect to the UE  500  if the angles correspond but the distances do not. The LOS/NLOS unit  550  is discussed further below, and the description may refer to the processor  510  generally, or the UE  500  generally, as performing any of the functions of the LOS/NLOS unit  550 . 
     Referring to  FIGS. 6 and 7 , with further reference to  FIGS. 1-5 , a signaling and process flow  600  for determining whether PRS is LOS, determining position information from LOS PRS, and determining map information from the position information includes the stages shown. The flow  600  is an example only, as stages may be added, rearranged, and/or removed. For example, the timing shown in  FIG. 6  is an example, as stages may occur in different orders than as shown (e.g., one or more reflection-based ranging stages occurring after one or more PRS exchanges). In the flow  600 , a target UE  700  interacts with an anchor UE  710 , an anchor UE  720 , an anchor UE  730 , a building  740 , a building  750 , and an RSU  605  (Roadside Unit), with the UEs  700 ,  710 ,  720 ,  730 , and the buildings  740 ,  750  disposed in a layout shown in  FIG. 7 . This is an example only, and other layouts and other quantities and types of entities are possible. The target UE  700  is an example of the UE  500 , and the anchor UEs  710 ,  720 ,  730  may be examples of the UE  500 , e.g., with or without the ranging system  540 . The RSU  605  may be an example of the TRP  300 . 
     At stage  610 , the target UE  700  performs reflection-based ranging to the anchor UE  710 , the anchor UE  730 , the building  740 , and the building  750 . For illustration purposes, the ranging system  540  begins transmitting ranging signals from 0° relative to the target UE  700  as shown in  FIG. 7 , and rotates the antenna  546  clockwise from the perspective of  FIG. 7 . Consequently, due to the layout shown in  FIG. 7 , the ranging system  540  encounters the building  740 , the building  750 , the anchor UE  710 , and the anchor UE  730  in that order. The ranging system  540  sends a ranging Tx signal  611  that is reflected by the building  740  to produce a ranging reflection signal  612  that is received by the ranging system  540 . Similarly, the ranging system  540  sends ranging Tx signals  613 ,  615 ,  617  that are respectively reflected by the building  750 , the anchor UE  710 , and the anchor UE  730 , to produce ranging reflection signals  614 ,  616 ,  618  that are received by the ranging system  540 . The ranging Tx signals  611 ,  613 ,  615 ,  617  may be, for example, radio frequency (RF) signals for a radar system, light signals for a lidar system, sound signals (e.g., ultrasound signals) for a sonar system, etc. 
     Ranges to the buildings  740 ,  750  and to the anchor UEs  710 ,  730  may be determined based on, e.g., upon receipt of, the respective ranging reflection signals  612 ,  614 ,  616 ,  618 . For each reflected ranging signal received, the ranging system  540  (e.g., the processor  548 ) determines the angle, relative to the target UE  700 , of the object that reflected the ranging Tx signal. For example, because the time for the ranging Tx signal to be sent, reflected, and the ranging reflection received by the target UE  700  will be nearly instantaneous for any object within range of the ranging system  540  (even considering the rotation of the beam and possible movement of the target UE  700 , such as a vehicle), the ranging system  540  may determine a present angle of the beam from the antenna  546  when the ranging reflection is received to be the angle of the object relative to the target UE  700 . The ranging system  540  may determine the distance to the object that reflects the ranging Tx signal (i.e., the distance to a reflector) using round trip time of the ranging Tx signal and the ranging reflection signal, and/or the transmit power of the ranging Tx signal and the received power of the ranging reflection signal. Further, the ranging system  540  (e.g., the processor  548 ) determines the respective distance to the reflector for each angle yielding a reflection. Referring also to  FIG. 8 , for the example layout of  FIG. 7 , analysis of the ranging Tx signals and ranging reflections yields four angles and four corresponding distances to reflectors (here, the buildings  740 ,  750  and the anchor UEs  710 ,  730 ). The ranging system  540  or the processor  510  may store the determined angles and distances in the memory  530 . In this example, the processor  548  determines from the ranging Tx signal  611  and the ranging reflection  612  that an object (here the building  740 ) is at 10° (with 0° relative to the target UE  700  directed as shown in  FIG. 7 ) at a distance of 120 m. The processor  548  determines from the ranging Tx signals  613 ,  615 ,  617  and the respective ranging reflection signals  614 ,  616 ,  618  that objects are disposed at 45°, 130°, and 164° relative to the target UE  700  at respective distances of 120 m, 250 m, 427 m from the target UE  700 . Here, the angles and distances are stored in a database  810  in entries  811 ,  812 ,  813 ,  814 . The ranging-system-determined angles in the database  810  form a set α of angles, and the ranging-system-determined distances form a set β (although α or β could each contain a single value or multiple values). 
     At stage  620 , the target UE  700  receives PRS from the anchor UEs  710 ,  720 ,  730 . The anchor UEs  710 ,  730  are LOS with the target UE  700  as shown in  FIG. 7 , while the anchor UE  720  is NLOS with the target UE  700 , with the building  740  disposed between the target UE  700  and the anchor UE  720 . Thus, the anchor UEs  710 ,  730  send PRS  621 ,  624  that travel directly to the target UE  700  while the anchor UE  720  sends PRS  622  that is reflected by the building  750  to produce a PRS reflection  623  that is received by the target UE  700 . The processor  510  may determine the AoA of each PRS, e.g., by determine the steering angle of the antenna(s)  526  when the PRS (or PRS reflection) was received. The processor  510  may also determine a respective distance traveled by each PRS from the respective anchor UE to the target UE  700 . For example, the anchor UEs  710 ,  720 ,  730  may send respective post-PRS signals  625 ,  626 ,  627  that indicate the respective time of departure of the PRS  621 ,  622 ,  624 , and the location of the respective anchor UE  710 ,  720 ,  730 . The processor  510  may receive indications of the times of departure, and obtain (e.g., from the memory  530 ) respective first times of arrival of each of the PRS  621 ,  624  and the PRS reflection  623 . The processor  510  may determine the distances traveled by the PRS  621 ,  624 , and the PRS  622  and the PRS reflection  623  based on differences of the respective times of departure of the PRS  621 ,  622 ,  624  and the respective first times of arrival of the PRS  621 ,  622  and the PRS reflection  623 , divided by the speed of light. If the processor  510  is configured to detect multiple receptions of the same PRS (e.g., the two strongest instances of a PRS), then multiple angles may be close together. Here, the AoAs and corresponding distances are stored in the memory  530  in a database  820  in entries  821 ,  822 ,  823 . The PRS-based angles in the database  820  form a set γ of angles, and the PRS-based distances in the database  820  form a set δ (although γ or δ could each contain a single value or multiple values). 
     At stage  630 , the target UE  700  determines whether each of the received PRS is from an anchor UE that is LOS or NLOS with respect to the target UE  700 . The LOS/NLOS unit  550  is configured to determine whether an AoA determined by the processor  510  corresponds to an object angle determined by the ranging system  540 . For example, the LOS/NLOS unit  550  may be configured to determine whether an angle in the set γ corresponds to an angle in the set α (i.e., whether γ x ∈α). An AoA may be considered to correspond to a ranging-system-determined angle if the AoA is within an angular threshold closeness (e.g., within a threshold number of degrees (e.g., 2° or 3° or 5°)) of the ranging-system-determined angle. The angular threshold may be dynamic, e.g., depending on an AoA accuracy achievable by processor  510  from analysis of the PRS (e.g., based on a number of antenna elements of the antenna(s)  526 , antenna element spacing, and/or duration of the ranging session, which may correlate to an AoA resolution achievable from analysis of signals received by the antennas  526 ). The ranging-system-determined angle may be a range of angles (e.g., a reflector may span a range of angles). The AoA may be considered to correspond to such a range of angles if the AoA is contained by the range of angles, or within a threshold closeness of either end of the range of angles. The LOS/NLOS unit  550  is configured to determine whether a distance determined by the processor  510  corresponds to an object distance determined by the ranging system  540  for an AoA that corresponds to a ranging-system-determined angle. For example, the LOS/NLOS unit  550  may be configured to determine, for an AoA γ x  that corresponds to a ranging-system-determined angle α x , whether the PRS-based distance δ x  for the AoA γ x  corresponds to the ranging-system-determined distance β x  for the angle α x . A PRS-based distance may be considered to correspond to a ranging-system-determined distance if the PRS-based distance is within a threshold closeness (e.g., within a threshold percentage (e.g., 5% or 10% or 20%)) of the ranging-system-determined distance. 
     The LOS/NLOS unit  550  may be configured to determine the LOS/NLOS status of an anchor UE based on the AoAs in γ and corresponding distances in δ and the ranging-system-determined angles in α and corresponding distances in β according to the following:
         If γ x  ∈α (with γ x ≈α y ) and δ x ≈β y , then anchor UE x  is LOS with target UE; or   If γ x ∈α (with γ x ≈α y ) and δ x   β y , then anchor UE x  is NLOS with target UE; or   If γ x ∉α, then LOS/NLOS status is indeterminate.
 
Thus, if a determined AoA (γ x ) is an element of the set α in that the AoA corresponds to (e.g., is within a threshold of) a ranging-system-determined angle (α y ) (i.e., γ x ∈α in that γ x ≈α y ) and the distance (δ x ) determined from the PRS for this AoA corresponds to (e.g., is within a threshold of) the ranging-system-determined distance (β y ) for the ranging-system-determined angle corresponding to the AoA (i.e., δ x ≈β y ), then the LOS/NLOS unit  550  determines that the respective anchor UE is LOS with the target UE  700 . For example, with an angle threshold of 3° and a distance threshold of 5%, the AoA of 127° (γ x ) of the entry  822  is within the threshold of the ranging-system-determined angle of 130° (α y ) of the entry  813 , and the PRS-determined distance of 254 m (δ x ) of the entry  822  is within the distance threshold of the ranging-system-determined distance of 250 m (β y ) of the entry  813 . The LOS/NLOS unit  550  will thus conclude that the anchor UE  710  (that sent the PRS from which the AoA of 127° was determined) is LOS with respect to the target UE  700 . Conversely, if a determined AoA (γ x ) is an element of the set α (e.g., γ x ≈α y ) and the respective PRS-determined distance (δ x ) does not correspond to (e.g., is outside a threshold closeness of) the ranging-system-determined distance (β y ) (i.e., δ x   β y ), then the LOS/NLOS unit  550  determines that the respective anchor UE is NLOS with the target UE  700 . For example, with an angle threshold of 3° and a distance threshold of 5%, the AoA of 48° (γ x ) of the entry  821  is within the threshold of the ranging-system-determined angle of 45° (α y ) of the entry  812 , and the PRS-determined distance of 215 m (δ x ) of the entry  821  is outside the distance threshold of the ranging-system-determined distance of 120 m (β y ) of the entry  812 . The PRS-determined distance of 215 m (for the PRS reflection  626 ) is much longer than the ranging-system-determined distance of 120 m (to the building  750 ) due to the extra path length of the PRS  624  from the anchor UE  720  to the building  750 . The LOS/NLOS unit  550  will thus conclude that the anchor UE  720  (that sent the PRS from which the AoA of 48° was determined) is NLOS with respect to the target UE  700 . If a determined AoA for a received PRS (or PRS reflection) does not correspond to a ranging-system-determined angle (i.e., γ x ∉α because γ x  is not within the angular threshold of any angle in the set α), then the LOS/NLOS unit  550  will conclude that the LOS/NLOS status of the corresponding anchor UE (corresponding to the AoA γ x ) is indeterminate, and use a conventional technique to determine the LOS/NLOS status of the anchor UE. For example, with an angle threshold of 3°, the AoA of 160° of the entry  823  is not within the angle threshold of any of the ranging-system-determined angles in the database  810 . The LOS/NLOS unit  550  will thus conclude that the LOS/NLOS status of the anchor UE  730  (that sent the PRS from which the AoA of 160° was determined, e.g., as determined from a PRS pattern corresponding to the anchor UE  730 ) is unsure, and in response may use one or more other techniques to determine the LOS/NLOS status of the anchor UE  730 .
       

     The LOS/NLOS unit  550  may be configured to use the angle set α and the distance set β to determine LOS/NLOS status of a PRS source for a limited time. Thus, a validity of the angle and distance sets may be time limited, e.g., because angles and distances to PRS sources will change as the UE  500  moves. The LOS/NLOS unit  550  may adjust a validity time based on motion of the UE  500 . For example, the LOS/NLOS unit  550  may extend the validity time indefinitely as long as the UE  500  is static. 
     Referring in particular again to  FIG. 6 , at stage  640 , the target UE  700  determines position information. For example, the processor  510  may one or more PRS measurements, one or more ranges, and/or one or more location estimates for the target UE  700 . One or more measurements (e.g., PRS measurements) and one or more ranges are determined at stage  630 , and one or more additional measurements and/or one or more additional ranges may be determined at stage  640 . The processor  510  may use the LOS/NLOS knowledge to select measurements only for PRS that were LOS to the UE  500  to determine the position information, which may improve the accuracy of the position information. 
     At stage  650 , the target UE provides capability information and position information to the server  400 . The target UE  500  may send a capability message  652  to the server  400  indicating that the target UE  700  has a reflection-based ranging system. The capability message may be separate from or included with a position information report  654  sent by the target UE  700  to the server  400 . The capability message  652  may be explicit or implicit (e.g., due to inclusion of one or more indications that LOS/NLOS for one or more corresponding PRS-based position information items was determined by reflection-based ranging). The position information report  654  may indicate whether position information was determined from PRS from a PRS source (e.g., an anchor UE) that was LOS or NLOS if the LOS/NLOS determination was made by the LOS/NLOS unit  550  (i.e., was not indeterminate). For example, for each PRS for which the corresponding anchor UE was determined to be LOS or NLOS, the position information derived from the PRS may be associated in the position information report  654  with an indication of LOS or NLOS, as appropriate. The position information report  654  may include the ranging-system-determined angle set a and the ranging-system-determined distance set β. While the target UE  700  sends the position report  654  to the server  400  in the flow  600 , the position report  654  may also or alternatively be sent to one or more other entities such as a static (stationary) UE, a roadside unit (RSU), etc. Other UEs may use Tx/Rx and LOS/NLOS pair information (e.g., Tx/Rx locations and whether there is an LOS or NLOS condition at the location(s)) regarding performing ranging at the indicated location(s) (e.g., saving energy by not attempting ranging at a location if an NLOS condition is indicated for the location). 
     Referring to  FIG. 9 , with further reference to  FIGS. 1-8 , a method  900  of determining a line-of-sight relationship between a UE and a PRS source includes the stages shown. The method  900  is, however, an example only and not limiting. The method  900  may be altered, e.g., by having stages added, removed, rearranged, combined, performed concurrently, and/or having single stages split into multiple stages. 
     At stage  910 , the method  900  includes transmitting a ranging signal. For example, the ranging system  540  sends a ranging signal such as an RF signal, a light signal, or a sound signal via the antenna  546 . As shown in  FIGS. 6 and 7 , the ranging system  540  sends ranging Tx signals  611 ,  613 ,  615 ,  617  toward the buildings  740 ,  750  and the anchor UEs  710 ,  730 . The processor  548 , possibly in combination with the memory  530 , and the wireless transmitter  542  and the antenna  546  may comprise means for transmitting the ranging signal. 
     At stage  920 , the method  900  includes receiving a reflection of the ranging signal. For example, one or more ranging signals hit one or more reflectors that reflect the ranging signal(s) and the ranging system  540  receives the reflection(s) of the ranging Tx signal(s). As shown in  FIGS. 6 and 7 , the ranging Tx signals  611 ,  613 ,  615 ,  617  are reflected into ranging reflection signals  612 ,  614 ,  616 ,  618  that the ranging system  540  receives. The processor  548 , possibly in combination with the memory  530  and/or the processor  510 , and the wireless receiver  544  and the antenna  546  may comprise means for receiving the reflection of the ranging signal. 
     At stage  930 , the method  900  includes determining, based on the ranging signal and the reflection of the ranging signal, (1) a first direction, between the UE and a reflector, and (2) a first distance, between the UE and the reflector, corresponding to the first direction. For example, the processor  548  uses information from the ranging Tx signal(s) and the ranging reflection signal(s) to determine angle and distance to a reflecting object (e.g., using time of departure and arrival of the transmitted and reflected signals and/or powers of the transmitted and reflected signals). The processor  548  may, for example, determine the angles and the distances in the database  810  in the example layout of  FIG. 7 . The processor  548 , possibly in combination with memory such as the memory  530 , may comprise means for determining the first direction and the first distance. 
     At stage  940 , the method  900  includes determining, based on a PRS received by the UE from the PRS source, (3) a second direction, corresponding to an angle of arrival of the PRS at the UE, and (4) a second distance, traveled by the PRS from the PRS source to the UE, corresponding to the second direction. For example, the processor  510  may analyze received PRS and post-PRS signaling to determine AoA to an anchor UE and distance from the anchor UE to the UE  500  along the path traveled by the PRS. For example, using the PRS  621 ,  624  and the PRS reflection  623  the processor  510  can determine times of arrival and from the post-PRS signals  625 - 627  the processor determines times of departure of the PRS  621 ,  622 ,  624 , from which the processor  510  determines travel time and thus estimated distance between the target UE  700  and the anchor UEs  710 ,  720 ,  730  as shown in the database  820 . The determined distance will not be the LOS distance if the PRS used to determine time of arrival was a PRS reflection. The processor  548 , possibly in combination with memory such as the memory  530 , may comprise means for determining direction and distance between the UE and the PRS source. 
     At stage  950 , the method  900  includes determining whether the second distance is a line-of-sight distance between the UE and the PRS source based on the first direction, the first distance, the second direction, and the second distance. For example, the LOS/NLOS unit  550  analyzes the determined angles and distances, e.g., in the databases  810 ,  820 , to determine LOS/NLOS status of one or more PRS sources, e.g., anchor UEs, relative to the UE. The processor  510 , possibly in combination with the memory  530 , may comprise means for determining whether the second distance is a line-of-sight distance between the UE and the PRS source. 
     Implementations of the method  900  may include one or more of the following features. In an example implementation, determining whether the second distance is the line-of-sight distance between the UE and the PRS source comprises determining that the second distance is the line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being within a second threshold closeness. For example, the LOS/NLOS unit  550  selects a PRS-determined angle (i.e., an AoA determined from received PRS) and first determines whether a ranging-system-determined angle corresponds to (e.g., is within a threshold closeness of) this PRS-determined angle. If the selected AoA corresponds to a ranging-system-determined angle, then the LOS/NLOS unit  550  may determine whether the respective distances (i.e., the PRS-determined distance and the ranging-system-determined distance) correspond (e.g., are within a threshold closeness). If the distances correspond, then the LOS/NLOS unit  550  determines that the PRS source is LOS with respect to the UE. In another example implementation, the method  900  comprises determining the first threshold based on an angular accuracy of the second direction. For example, the LOS/NLOS unit  550  may select a value of the first threshold based on one or more indications of an accuracy of the PRS-determined angle (e.g., an indication of an error range of a determined angle). The processor  510 , possibly in combination with the memory  530 , possibly in combination with the interface  520  (e.g., the wireless receiver  524  and the antenna(s)  526 ), may comprise means for determining the first threshold. In another example implementation, determining the first threshold comprises determining the first threshold based on a quantity of antenna elements used to determine the second direction between the UE and the PRS source. For example, the LOS/NLOS unit  550  may select a value of the first threshold based on an indication of the number of antenna elements that were used to receive the PRS because that quantity may be directly related to a resolution of the AoA. 
     Also or alternatively, implementations of the method  900  may include one or more of the following features. In an example implementation, determining whether the second distance is the line-of-sight distance between the UE and the PRS source comprises determining that the second distance is a non-line-of-sight distance between the UE and the PRS source based on the first direction and the second direction being within a first threshold closeness and based on the first distance and the second distance being outside of a second threshold closeness. For example, the LOS/NLOS unit  550  selects a PRS-determined angle (i.e., an AoA determined from received PRS) and first determines whether a ranging-system-determined angle corresponds to (e.g., is within a threshold closeness of) this PRS-determined angle. If the selected AoA corresponds to a ranging-system-determined angle, then the LOS/NLOS unit  550  may determine whether the respective distances (i.e., the PRS-determined distance and the ranging-system-determined distance) correspond (e.g., are within a threshold closeness). If the distances do not correspond, then the LOS/NLOS unit  550  determines that the PRS source is NLOS with respect to the UE. In another example implementation, the method  900  comprises sending a report comprising position information determined from the one or more PRS and at least one line-of-sight/non-line-of-sight indication indicating whether the position information is based on a line-of-sight measurement or a non-line-of-sight measurement. For example, the LOS/NLOS unit  550  may send the position information report  654  to another entity (e.g., the server  400 , the TRP  300 , a roadside unit, etc.), with the report  654  indicating position information (e.g., one or more measurements and/or one or more location estimates for the UE  500 ) and whether the position information was determined using a PRS from a source that was LOS or NLOS with respect to the UE  500 . The processor, possibly in combination with the memory, in combination with the interface  520  (e.g., the wireless transmitter  522  and the antenna(s)  526  and/or a wired transmitter) may comprise means for sending the report. 
     Other Considerations 
     Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software and computers, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or a combination of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. 
     As used herein, the singular forms “a,” “an,” and “the” include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “includes,” and/or “including,” as used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     As used herein, the term RS (reference signal) may refer to one or more reference signals and may apply, as appropriate, to any form of the term RS, e.g., PRS, SRS, CSI-RS, etc. 
     As used herein, unless otherwise stated, a statement that a function or operation is “based on” an item or condition means that the function or operation is based on the stated item or condition and may be based on one or more items and/or conditions in addition to the stated item or condition. 
     Also, as used herein, “or” as used in a list of items prefaced by “at least one of” or prefaced by “one or more of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C,” or a list of “one or more of A, B, or C” means A, or B, or C, or AB (A and B), or AC (A and C), or BC (B and C), or ABC (i.e., A and B and C), or combinations with more than one feature (e.g., AA, AAB, ABBC, etc.). Thus, a recitation that an item, e.g., a processor, is configured to perform a function regarding at least one of A or B means that the item may be configured to perform the function regarding A, or may be configured to perform the function regarding B, or may be configured to perform the function regarding A and B. For example, a phrase of “a processor configured to measure at least one of A or B” means that the processor may be configured to measure A (and may or may not be configured to measure B), or may be configured to measure B (and may or may not be configured to measure A), or may be configured to measure A and measure B (and may be configured to select which, or both, of A and B to measure). Similarly, a recitation of a means for measuring at least one of A or B includes means for measuring A (which may or may not be able to measure B), or means for measuring B (and may or may not be configured to measure A), or means for measuring A and B (which may be able to select which, or both, of A and B to measure). As another example, a recitation that an item, e.g., a processor, is configured to at least one of perform function X or perform function Y means that the item may be configured to perform the function X, or may be configured to perform the function Y, or may be configured to perform the function X and to perform the function Y. For example, a phrase of “a processor configured to at least one of measure X or measure Y” means that the processor may be configured to measure X (and may or may not be configured to measure Y), or may be configured to measure Y (and may or may not be configured to measure X), or may be configured to measure X and to measure Y (and may be configured to select which, or both, of X and Y to measure). 
     Substantial variations may be made in accordance with specific requirements. For example, customized hardware might also be used, and/or particular elements might be implemented in hardware, software (including portable software, such as applets, etc.) executed by a processor, or both. Further, connection to other computing devices such as network input/output devices may be employed. Components, functional or otherwise, shown in the figures and/or discussed herein as being connected or communicating with each other are communicatively coupled unless otherwise noted. That is, they may be directly or indirectly connected to enable communication between them. 
     The systems and devices discussed above are examples. Various configurations may omit, substitute, or add various procedures or components as appropriate. For instance, features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Also, technology evolves and, thus, many of the elements are examples and do not limit the scope of the disclosure or claims. 
     A wireless communication system is one in which communications are conveyed wirelessly, i.e., by electromagnetic and/or acoustic waves propagating through atmospheric space rather than through a wire or other physical connection. A wireless communication network may not have all communications transmitted wirelessly, but is configured to have at least some communications transmitted wirelessly. Further, the term “wireless communication device,” or similar term, does not require that the functionality of the device is exclusively, or evenly primarily, for communication, or that the device be a mobile device, but indicates that the device includes wireless communication capability (one-way or two-way), e.g., includes at least one radio (each radio being part of a transmitter, receiver, or transceiver) for wireless communication. 
     Specific details are given in the description to provide a thorough understanding of example configurations (including implementations). However, configurations may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the configurations. This description provides example configurations only, and does not limit the scope, applicability, or configurations of the claims. Rather, the preceding description of the configurations provides a description for implementing described techniques. Various changes may be made in the function and arrangement of elements. 
     The terms “processor-readable medium,” “machine-readable medium,” and “computer-readable medium,” as used herein, refer to any medium that participates in providing data that causes a machine to operate in a specific fashion. Using a computing platform, various processor-readable media might be involved in providing instructions/code to processor(s) for execution and/or might be used to store and/or carry such instructions/code (e.g., as signals). In many implementations, a processor-readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media include, for example, optical and/or magnetic disks. Volatile media include, without limitation, dynamic memory. 
     Having described several example configurations, various modifications, alternative constructions, and equivalents may be used. For example, the above elements may be components of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of operations may be undertaken before, during, or after the above elements are considered. Accordingly, the above description does not bound the scope of the claims. 
     A statement that a value exceeds (or is more than or above) a first threshold value is equivalent to a statement that the value meets or exceeds a second threshold value that is slightly greater than the first threshold value, e.g., the second threshold value being one value higher than the first threshold value in the resolution of a computing system. A statement that a value is less than (or is within or below) a first threshold value is equivalent to a statement that the value is less than or equal to a second threshold value that is slightly lower than the first threshold value, e.g., the second threshold value being one value lower than the first threshold value in the resolution of a computing system.