Patent Description:
Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (<NUM>), a second-generation (<NUM>) digital wireless phone service (including interim <NUM> and <NUM> networks), a third-generation (<NUM>) high speed data, Internet-capable wireless service and a fourth-generation (<NUM>) service (e.g., Long Term Evolution (LTE) or WiMax). 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), Time Division Multiple Access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, etc..

A fifth generation (<NUM>) mobile standard calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The <NUM> 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 <NUM> 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 <NUM> mobile communications should be significantly enhanced compared to the current <NUM> standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.

Some wireless communication networks, such as <NUM>, support operation at very high and even extremely-high frequency (EHF) bands, such as millimeter wave (mmW) frequency bands (generally, wavelengths of <NUM> to <NUM>, or <NUM> to <NUM>). These extremely high frequencies may support very high throughput such as up to six gigabits per second (Gbps). One of the challenges for wireless communication at very high or extremely high frequencies, however, is that a significant propagation loss may occur due to the high frequency. As the frequency increases, the wavelength may decrease, and the propagation loss may increase as well. At mmW frequency bands, the propagation loss may be severe. For example, the propagation loss may be on the order of <NUM> to <NUM> dB, relative to that observed in either the <NUM>, or <NUM> bands.

Propagation loss is also an issue in Multiple Input-Multiple Output (MIMO) and massive MIMO systems in any band. The term MIMO as used herein will generally refer to both MIMO and massive MIMO. MIMO is a method for multiplying the capacity of a radio link by using multiple transmit and receive antennas to exploit multipath propagation. Multipath propagation occurs because radio frequency (RF) signals not only travel by the shortest path between the transmitter and receiver, which may be a line of sight (LOS) path, but also over a number of other paths as they spread out from the transmitter and reflect off other objects such as hills, buildings, water, and the like on their way to the receiver. A transmitter in a MIMO system includes multiple antennas and takes advantage of multipath propagation by directing these antennas to each transmit the same RF signals on the same radio channel to a receiver. The receiver is also equipped with multiple antennas tuned to the radio channel that can detect the RF signals sent by the transmitter. As the RF signals arrive at the receiver (some RF signals may be delayed due to the multipath propagation), the receiver can combine them into a single RF signal. Because the transmitter sends each RF signal at a lower power level than it would send a single RF signal, propagation loss is also an issue in a MIMO system.

To address propagation loss issues in mmW band systems and MIMO systems, transmitters may use beamforming to extend RF signal coverage. In particular, transmit beamforming is a technique for emitting an RF signal in a specific direction, whereas receive beamforming is a technique used to increase receive sensitivity of RF signals that arrive at a receiver along a specific direction. Transmit beamforming and receive beamforming may be used in conjunction with each other or separately, and references to "beamforming" may hereinafter refer to transmit beamforming, receive beamforming, or both. Traditionally, when a transmitter broadcasts an RF signal, it broadcasts the RF signal in nearly all directions determined by the fixed antenna pattern or radiation pattern of the antenna. With beamforming, the transmitter determines where a given receiver is located relative to the transmitter and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal for the receiver. To change the directionality of the RF signal when transmitting, a transmitter can control the phase and relative amplitude of the RF signal broadcasted by each antenna. For example, a transmitter may use an array of antennas (also referred to as a "phased array" or an "antenna array") that creates a beam of RF waves that can be "steered" to point in different directions, without actually moving the antennas. Specifically, the RF current is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling the radio waves from the separate antennas to suppress radiation in undesired directions.

To support position estimations in terrestrial wireless networks, a mobile device can be configured to measure and report the observed time difference of arrival (OTDOA) or reference signal timing difference (RSTD) between reference RF signals received from two or more network nodes (e.g., different base stations or different transmission points (e.g., antennas) belonging to the same base station).

Where a transmitter uses beamforming to transmit RF signals, the beams of interest for data communication between the transmitter and receiver will be the beams carrying RF signals having the highest received signal strength (or highest received Signal to Noise plus Interference Ratio (SINR), for example, in the presence of a directional interfering signal). However, the receiver's ability to perform certain tasks may suffer when the receiver relies upon the beam with the highest received signal strength. For example, in a scenario where the beam with the highest received signal strength travels over a non-LOS (NLOS) path that is longer than the shortest path (i.e., a LOS path or a shortest NLOS path), the RF signals may arrive later than RF signal(s) received over the shortest path due to propagation delay. Accordingly, if the receiver is performing a task that requires precise timing measurements, and the beam with the highest received signal strength is affected by longer propagation delay, then the beam with the highest received signal strength may not be optimal for the task at hand.

PCT application with publication number <CIT> discloses systems and methods that relate wireless positioning based on cell portion specific Positioning Reference Signals (PRSs) by multiple Transmission Points (TPs) in a shared cell. In some embodiments, a method of operation of a TP in a cellular communications network is provided.

<CIT> discloses solutions for using a mix of reference signal types in a wireless communications network, e.g. a first type and a second type, in making positioning-related measurements. In one example, a UE uses a "mix" of CRS and PRS.

US patent application with publication number <CIT> discloses a method of determining a position of a terminal in a communication system using multiple beams. The method includes receiving a first beam from a first point, receiving a second beam from a second point, and determining a position of the terminal by use of information about the first beam and information about the second beam, so that in a case in which two or more effective beams are received in a system using multiple beams, the position of the terminal is determined by use of the angle of a beam, and information about the coordinates of departure of a beam and / or coordinates of final arrival of a beam without using a positioning device, such as GPS.

A more complete appreciation of the various aspects described herein and many attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings which are presented solely for illustration and not limitation, and in which:.

Various aspects described herein generally relate to exchanging location information of a base station that is associated with a plurality of different transmission point locations. In an embodiment, a user equipment (UE) receives, from a network entity (e.g., a base station, a server, etc.), at least one base station almanac (BSA) message that indicates (i) a set of transmission point locations associated with at least one base station, the set of transmission point locations including at least one transmission point location of a base station that is based upon a plurality of different transmission point locations associated with the base station, and (ii) a mapping of each of a plurality of beams to the at least one transmission point location. The UE receives, from the base station, the plurality of beams in accordance with the mapping. The UE then estimates a position of the UE based at least in part upon (i) one or more measurements performed by the UE on one or more of the plurality of beams and (ii) the at least one transmission point location to which the one or more beams are mapped.

These and other aspects are disclosed in the following description and related drawings to show specific examples relating to exemplary aspects. Alternate aspects will be apparent to those skilled in the pertinent art upon reading this disclosure, and may be constructed and practiced without departing from the scope of the disclosure. Additionally, well-known elements will not be described in detail or may be omitted so as to not obscure the relevant details of the aspects disclosed herein.

Likewise, the term "aspects" does not require that all aspects include the discussed feature, advantage, or mode of operation.

The terminology used herein describes particular aspects only and should not be construed to limit any aspects disclosed herein. Those skilled in the art will further understand that 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.

Further, various aspects may be described in terms of sequences of actions to be performed by, for example, elements of a computing device. Those skilled in the art will recognize that 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. Additionally, these sequences of actions described herein can be considered to be embodied entirely within any form of 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 have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspects may be described herein as, for example, "logic configured to" and/or other structural components configured to perform the described action.

As used herein, the terms "user equipment" (or "UE"), "user device," "user terminal," "client device," "communication device," "wireless device," "wireless communications device," "handheld device," "mobile device," "mobile terminal," "mobile station," "handset," "access terminal," "subscriber device," "subscriber terminal," "subscriber station," "terminal," and variants thereof may interchangeably refer to any suitable mobile or stationary device that can receive wireless communication and/or navigation signals. These terms are also intended to include devices which communicate with another device that can receive wireless communication and/or navigation signals such as by short-range wireless, infrared, wireline connection, or other connection, regardless of whether satellite signal reception, assistance data reception, and/or position-related processing occurs at the device or at the other device. In addition, these terms are intended to include all devices, including wireless and wireline communication devices, that can communicate with a core network via a radio access network (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 a wired access network, a wireless local area network (WLAN) (e.g., based on IEEE <NUM>, etc.) and so on. UEs can 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, 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.

According to various aspects, <FIG> illustrates an exemplary wireless communications system <NUM>. The wireless communications system <NUM> (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations <NUM> and various UEs <NUM>. The base stations <NUM> may include macro cells (high power cellular base stations) and/or small cells (low power cellular base stations), wherein the macro cells may include Evolved NodeBs (eNBs), where the wireless communications system <NUM> corresponds to an LTE network, or gNodeBs (gNBs), where the wireless communications system <NUM> corresponds to a <NUM> network or a combination of both, and the small cells may include femtocells, picocells, microcells, etc..

The base stations <NUM> may collectively form a Radio Access Network (RAN) and interface with an Evolved Packet Core (EPC) or Next Generation Core (NGC) through backhaul links. In addition to other functions, the base stations <NUM> may perform functions that relate to one or more of transferring user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations <NUM> may communicate with each other directly or indirectly (e.g., through the EPC / NGC) over backhaul links <NUM>, which may be wired or wireless.

In an aspect, although not shown in <FIG>, geographic coverage areas <NUM> may be subdivided into a plurality of cells (e.g., three), or sectors, each cell corresponding to a single antenna or array of antennas of a base station <NUM>. As used herein, the term "cell" or "sector" may correspond to one of a plurality of cells of a base station <NUM>, or to the base station <NUM> itself, depending on the context.

While neighboring macro cell geographic coverage areas <NUM> may partially overlap (e.g., in a handover region), some of the geographic coverage areas <NUM> may be substantially overlapped by a larger geographic coverage area <NUM>. For example, a small cell base station <NUM>' may have a geographic coverage area <NUM>' that substantially overlaps with the geographic coverage area <NUM> of one or more macro cell base stations <NUM>. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home eNBs (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links <NUM> may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links <NUM> may be through one or more carriers. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

When communicating in an unlicensed frequency spectrum, the WLAN STAs <NUM> and/or the WLAN AP <NUM> may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

When operating in an unlicensed frequency spectrum, the small cell base station <NUM>' may employ LTE or <NUM> technology and use the same <NUM> unlicensed frequency spectrum as used by the WLAN AP <NUM>. LTE in an unlicensed spectrum may be referred to as LTE-unlicensed (LTE-U), licensed assisted access (LAA), or MulteFire.

The wireless communications system <NUM> may further include a mmW base station <NUM> that may operate in mmW frequencies and/or near mmW frequencies in communication with a UE <NUM>. Further, it will be appreciated that in alternative configurations, one or more base stations <NUM> may also transmit using mmW or near mmW and beamforming <NUM>.

The wireless communications system <NUM> may further include one or more UEs, such as UE <NUM>, that connects indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. In the embodiment of <FIG>, UE <NUM> has a D2D P2P link <NUM> with one of the UEs <NUM> connected to one of the base stations <NUM> (e.g., through which UE <NUM> may indirectly obtain cellular connectivity) and a D2D P2P link <NUM> with WLAN STA <NUM> connected to the WLAN AP <NUM> (through which UE <NUM> may indirectly obtain WLAN-based Internet connectivity). In an example, the D2D P2P links <NUM>-<NUM> may be supported with any well-known D2D radio access technology (RAT), such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth, and so on.

According to various aspects, <FIG> illustrates an example wireless network structure <NUM>. For example, a Next Generation Core (NGC) <NUM> can be viewed functionally as control plane functions <NUM> (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane functions <NUM>, (e.g., UE gateway function, access to data networks, IP routing, etc.) which operate cooperatively to form the core network. User plane interface (NG-U) <NUM> and control plane interface (NG-C) <NUM> connect the gNB <NUM> to the NGC <NUM> and specifically to the control plane functions <NUM> and user plane functions <NUM>. In an additional configuration, an eNB <NUM> may also be connected to the NGC <NUM> via NG-C <NUM> to the control plane functions <NUM> and NG-U <NUM> to user plane functions <NUM>. Further, eNB <NUM> may directly communicate with gNB <NUM> via a backhaul connection <NUM>. Accordingly, in some configurations, the New RAN <NUM> may only have one or more gNBs <NUM>, while other configurations include one or more of both eNBs <NUM> and gNBs <NUM>. Either gNB <NUM> or eNB <NUM> may communicate with UEs <NUM> (e.g., any of the UEs depicted in <FIG>, such as UEs <NUM>, UE <NUM>, UE <NUM>, etc.). Another optional aspect may include Location Server <NUM> which may be in communication with the NGC <NUM> to provide location assistance for UEs <NUM>. The location server <NUM> can be implemented as a plurality of structurally separate servers, or alternately may each correspond to a single server. The location server <NUM> can be configured to support one or more location services for UEs <NUM> that can connect to the location server <NUM> via the core network, NGC <NUM>, and/or via the Internet (not illustrated). Further, the location server <NUM> may be integrated into a component of the core network, or alternatively may be external to the core network.

According to various aspects, <FIG> illustrates another example wireless network structure <NUM>. For example, Evolved Packet Core (EPC) <NUM> can be viewed functionally as control plane functions, Mobility Management Entity (MME) <NUM> and user plane functions, Packet Data Network Gateway / Serving Gateway (P/SGW) <NUM>, which operate cooperatively to form the core network. S1 user plane interface (S1-U) <NUM> and S1 control plane interface (S1-MME) <NUM> connect the eNB <NUM> to the EPC <NUM> and specifically to MME <NUM> and P/SGW <NUM>. In an additional configuration, a gNB <NUM> may also be connected to the EPC <NUM> via S1-MME <NUM> to MME <NUM> and S1-U <NUM> to P/SGW <NUM>. Further, eNB <NUM> may directly communicate to gNB <NUM> via the backhaul connection <NUM>, with or without gNB <NUM> direct connectivity to the EPC <NUM>. Accordingly, in some configurations, the New RAN <NUM> may only have one or more gNBs <NUM>, while other configurations include one or more of both eNBs <NUM> and gNBs <NUM>. Either gNB <NUM> or eNB <NUM> may communicate with UEs <NUM> (e.g., any of the UEs depicted in <FIG>, such as UEs <NUM>, UE <NUM>, UE <NUM>, etc.). Another optional aspect may include Location Server <NUM> which may be in communication with the EPC <NUM> to provide location assistance for UEs <NUM>. The location server <NUM> can be implemented as a plurality of structurally separate servers, or alternately may each correspond to a single server. The location server <NUM> can be configured to support one or more location services for UEs <NUM> that can connect to the location server <NUM> via the core network, EPC <NUM>, and/or via the Internet (not illustrated).

According to various aspects, <FIG> illustrates an exemplary base station <NUM> (e.g., an eNB, a gNB, a small cell AP, a WLAN AP, etc.) in communication with an exemplary UE <NUM> in a wireless network. In the DL, IP packets from the core network (NGC <NUM> / EPC <NUM>) may be provided to a controller/processor <NUM>. The controller/processor <NUM> implements functionality for a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor <NUM> provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

The transmit (TX) processor <NUM> and the receive (RX) processor <NUM> implement Layer-<NUM> functionality associated with various signal processing functions. Layer-<NUM>, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. Each spatial stream may then be provided to one or more different antennas <NUM> via a separate transmitter 318TX.

Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the RX processor <NUM>. The TX processor <NUM> and the RX processor <NUM> implement Layer-<NUM> functionality associated with various signal processing functions. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station <NUM> on the physical channel. The data and control signals are then provided to the controller/processor <NUM>, which implements Layer-<NUM> and Layer-<NUM> functionality.

In the UL, the controller/processor <NUM> provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the core network. The controller/processor <NUM> is also responsible for error detection.

Similar to the functionality described in connection with the DL transmission by the base station <NUM>, the controller/processor <NUM> provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator <NUM> from a reference signal or feedback transmitted by the base station <NUM> may be used by the TX processor <NUM> to select the appropriate coding and modulation schemes, and to facilitate spatial processing.

IP packets from the controller/processor <NUM> may be provided to the core network. The controller/processor <NUM> is also responsible for error detection.

<FIG> illustrates an exemplary server 300B. In an example, the server 300B may correspond to one example configuration of the location server <NUM> described above. In <FIG>, the server 300B includes a processor 301B coupled to volatile memory 302B and a large capacity nonvolatile memory, such as a disk drive 303B. The server 300B may also include a floppy disc drive, compact disc (CD) or DVD disc drive 306B coupled to the processor 301B. The server 300B may also include network access ports 304B coupled to the processor 301B for establishing data connections with a network 307B, such as a local area network coupled to other broadcast system computers and servers or to the Internet.

<FIG> illustrates an exemplary wireless communications system <NUM> according to various aspects of the disclosure. In the example of <FIG>, a UE <NUM>, which may correspond to any of the UEs described above with respect to <FIG> (e.g., UEs <NUM>, UE <NUM>, UE <NUM>, etc.), is attempting to calculate an estimate of its position, or assist another entity (e.g., a base station or core network component, another UE, a location server, a third party application, etc.) to calculate an estimate of its position. The UE <NUM> may communicate wirelessly with a plurality of base stations 402a-d (collectively, base stations <NUM>), which may correspond to any combination of base stations <NUM> or <NUM> and/or WLAN AP <NUM> in <FIG>, using RF signals and standardized protocols for the modulation of the RF signals and the exchange of information packets. By extracting different types of information from the exchanged RF signals, and utilizing the layout of the wireless communications system <NUM> (i.e., the base stations locations, geometry, etc.), the UE <NUM> may determine its position, or assist in the determination of its position, in a predefined reference coordinate system. In an aspect, the UE <NUM> may specify its position using a two-dimensional coordinate system; however, the aspects disclosed herein are not so limited, and may also be applicable to determining positions using a three-dimensional coordinate system, if the extra dimension is desired. Additionally, while <FIG> illustrates one UE <NUM> and four base stations <NUM>, as will be appreciated, there may be more UEs <NUM> and more or fewer base stations <NUM>.

To support position estimates, the base stations <NUM> may be configured to broadcast reference RF signals (e.g., Positioning Reference Signals (PRS), Cell-specific Reference Signals (CRS), Channel State Information Reference Signals (CSI-RS), synchronization signals, etc.) to UEs <NUM> in their coverage areas to enable a UE <NUM> to measure reference RF signal timing differences (e.g., OTDOA or RSTD) between pairs of network nodes and/or to identify the beam that best excite the LOS or shortest radio path between the UE <NUM> and the transmitting base stations <NUM>. Identifying the LOS/shortest path beam(s) is of interest not only because these beams can subsequently be used for OTDOA measurements between a pair of base stations <NUM>, but also because identifying these beams can directly provide some positioning information based on the beam direction. Moreover, these beams can subsequently be used for other position estimation methods that require precise ToA, such as round-trip time estimation based methods.

As used herein, a "network node" may be a base station <NUM>, a cell of a base station <NUM>, a remote radio head, an antenna of a base station <NUM>, where the locations of the antennas of a base station <NUM> are distinct from the location of the base station <NUM> itself, or any other network entity capable of transmitting reference signals. Further, as used herein, a "node" may refer to either a network node or a UE.

A location server (e.g., location server <NUM>) may send assistance data to the UE <NUM> that includes an identification of one or more neighbor cells of base stations <NUM> and configuration information for reference RF signals transmitted by each neighbor cell. Alternatively, the assistance data can originate directly from the base stations <NUM> themselves (e.g., in periodically broadcasted overhead messages, etc.). Alternatively, the UE <NUM> can detect neighbor cells of base stations <NUM> itself without the use of assistance data. The UE <NUM> (e.g., based in part on the assistance data, if provided) can measure and (optionally) report the OTDOA from individual network nodes and/or RSTDs between reference RF signals received from pairs of network nodes. Using these measurements and the known locations of the measured network nodes (i.e., the base station(s) <NUM> or antenna(s) that transmitted the reference RF signals that the UE <NUM> measured), the UE <NUM> or the location server can determine the distance between the UE <NUM> and the measured network nodes and thereby calculate the location of the UE <NUM>.

The term "position estimate" is used herein to refer to an estimate of a position for a UE <NUM>, which may be geographic (e.g., may comprise a latitude, longitude, and possibly altitude) or civic (e.g., may comprise a street address, building designation, or precise point or area within or nearby to a building or street address, such as a particular entrance to a building, a particular room or suite in a building, or a landmark such as a town square). A position estimate may also be referred to as a "location," a "position," a "fix," a "position fix," a "location fix," a "location estimate," a "fix estimate," or by some other term. The means of obtaining a location estimate may be referred to generically as "positioning," "locating," or "position fixing. " A particular solution for obtaining a position estimate may be referred to as a "position solution. " A particular method for obtaining a position estimate as part of a position solution may be referred to as a "position method" or as a "positioning method.

The term "base station" may refer to a single physical transmission point or to multiple physical transmission points that may or may not be co-located. For example, where the term "base station" refers to a single physical transmission point, the physical transmission point may be an antenna of the base station (e.g., base station <NUM>) corresponding to a cell of the base station. Where the term "base station" refers to multiple co-located physical transmission points, the physical transmission points may be an array of antennas (e.g., as in a MIMO system or where the base station employs beamforming) of the base station. Where the term "base station" refers to multiple non-co-located physical transmission points, the physical transmission points may be a Distributed Antenna System (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a Remote Radio Head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical transmission points may be the serving base station receiving the measurement report from the UE (e.g., UE <NUM>) and a neighbor base station whose reference RF signals the UE is measuring. Thus, <FIG> illustrates an aspect in which base stations 402a and 402b form a DAS / RRH <NUM>. For example, the base station 402a may be the serving base station of the UE <NUM> and the base station 402b may be a neighbor base station of the UE <NUM>. As such, the base station 402b may be the RRH of the base station 402a. The base stations 402a and 402b may communicate with each other over a wired or wireless link <NUM>.

To accurately determine the position of the UE <NUM> using the OTDOAs and/or RSTDs between RF signals received from pairs of network nodes, the UE <NUM> needs to measure the reference RF signals received over the LOS path (or the shortest NLOS path where an LOS path is not available), between the UE <NUM> and a network node (e.g., base station <NUM>, antenna). However, RF signals travel not only by the LOS / shortest path between the transmitter and receiver, but also over a number of other paths as the RF signals spread out from the transmitter and reflect off other objects such as hills, buildings, water, and the like on their way to the receiver. Thus, <FIG> illustrates a number of LOS paths <NUM> and a number of NLOS paths <NUM> between the base stations <NUM> and the UE <NUM>. Specifically, <FIG> illustrates base station 402a transmitting over an LOS path 410a and an NLOS path 412a, base station 402b transmitting over an LOS path 410b and two NLOS paths 412b, base station 402c transmitting over an LOS path 410c and an NLOS path 412c, and base station 402d transmitting over two NLOS paths 412d. As illustrated in <FIG>, each NLOS path <NUM> reflects off some object <NUM> (e.g., a building). As will be appreciated, each LOS path <NUM> and NLOS path <NUM> transmitted by a base station <NUM> may be transmitted by different antennas of the base station <NUM> (e.g., as in a MIMO system), or may be transmitted by the same antenna of a base station <NUM> (thereby illustrating the propagation of an RF signal). Further, as used herein, the term "LOS path" refers to the shortest path between a transmitter and receiver, and may not be an actual LOS path, but rather, the shortest NLOS path.

In an aspect, one or more of base stations <NUM> may be configured to use beamforming to transmit RF signals. In that case, some of the available beams may focus the transmitted RF signal along the LOS paths <NUM> (e.g., the beams produce highest antenna gain along the LOS paths) while other available beams may focus the transmitted RF signal along the NLOS paths <NUM>. A beam that has high gain along a certain path and thus focuses the RF signal along that path may still have some RF signal propagating along other paths; the strength of that RF signal naturally depends on the beam gain along those other paths. An "RF signal" comprises an electromagnetic wave that transports information through the space between the transmitter and the receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, as described further below, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels.

Where a base station <NUM> uses beamforming to transmit RF signals, the beams of interest for data communication between the base station <NUM> and the UE <NUM> will be the beams carrying RF signals that arrive at UE <NUM> with the highest signal strength (as indicated by, e.g., the Received Signal Received Power (RSRP) or SINR in the presence of a directional interfering signal), whereas the beams of interest for position estimation will be the beams carrying RF signals that excite the shortest path or LOS path (e.g., an LOS path <NUM>). In some frequency bands and for antenna systems typically used, these will be the same beams. However, in other frequency bands, such as mmW, where typically a large number of antenna elements can be used to create narrow transmit beams, they may not be the same beams. As described below with reference to <FIG>, in some cases, the signal strength of RF signals on the LOS path <NUM> may be weaker (e.g., due to obstructions) than the signal strength of RF signals on an NLOS path <NUM>, over which the RF signals arrive later due to propagation delay.

<FIG> illustrates an exemplary wireless communications system <NUM> according to various aspects of the disclosure. In the example of <FIG>, a UE <NUM>, which may correspond to UE <NUM> in <FIG>, is attempting to calculate an estimate of its position, or to assist another entity (e.g., a base station or core network component, another UE, a location server, a third party application, etc.) to calculate an estimate of its position. The UE <NUM> may communicate wirelessly with a base station <NUM>, which may correspond to one of base stations <NUM> in <FIG>, using RF signals and standardized protocols for the modulation of the RF signals and the exchange of information packets.

As illustrated in <FIG>, the base station <NUM> is utilizing beamforming to transmit a plurality of beams <NUM> - <NUM> of RF signals. Each beam <NUM> - <NUM> may be formed and transmitted by an array of antennas of the base station <NUM>. Although <FIG> illustrates a base station <NUM> transmitting five beams <NUM> - <NUM>, as will be appreciated, there may be more or fewer than five beams, beam shapes such as peak gain, width, and side-lobe gains may differ amongst the transmitted beams, and some of the beams may be transmitted by a different base station.

A beam index may be assigned to each of the plurality of beams <NUM> - <NUM> for purposes of distinguishing RF signals associated with one beam from RF signals associated with another beam. Moreover, the RF signals associated with a particular beam of the plurality of beams <NUM> - <NUM> may carry a beam index indicator. A beam index may also be derived from the time of transmission, e.g., frame, slot and/or OFDM symbol number, of the RF signal. The beam index indicator may be, for example, a three-bit field for uniquely distinguishing up to eight beams. If two different RF signals having different beam indices are received, this would indicate that the RF signals were transmitted using different beams. If two different RF signals share a common beam index, this would indicate that the different RF signals are transmitted using the same beam. Another way to describe that two RF signals are transmitted using the same beam is to say that the antenna port(s) used for the transmission of the first RF signal are spatially quasi-collocated with the antenna port(s) used for the transmission of the second RF signal.

In the example of <FIG>, the UE <NUM> receives an NLOS data stream <NUM> of RF signals transmitted on beam <NUM> and an LOS data stream <NUM> of RF signals transmitted on beam <NUM>. Although <FIG> illustrates the NLOS data stream <NUM> and the LOS data stream <NUM> as single lines (dashed and solid, respectively), as will be appreciated, the NLOS data stream <NUM> and the LOS data stream <NUM> may each comprise multiple rays (i.e., a "cluster") by the time they reach the UE <NUM> due, for example, to the propagation characteristics of RF signals through multipath channels. For example, a cluster of RF signals is formed when an electromagnetic wave is reflected off of multiple surfaces of an object, and reflections arrive at the receiver (e.g., UE <NUM>) from roughly the same angle, each travelling a few wavelengths (e.g., centimeters) more or less than others. A "cluster" of received RF signals generally corresponds to a single transmitted RF signal.

In the example of <FIG>, the NLOS data stream <NUM> is not originally directed at the UE <NUM>, although, as will be appreciated, it could be, as are the RF signals on the NLOS paths <NUM> in <FIG>. However, it is reflected off a reflector <NUM> (e.g., a building) and reaches the UE <NUM> without obstruction, and therefore, may still be a relatively strong RF signal. In contrast, the LOS data stream <NUM> is directed at the UE <NUM> but passes through an obstruction <NUM> (e.g., vegetation, a building, a hill, a disruptive environment such as clouds or smoke, etc.), which may significantly degrade the RF signal. As will be appreciated, although the LOS data stream <NUM> is weaker than the NLOS data stream <NUM>, the LOS data stream <NUM> will arrive at the UE <NUM> before the NLOS data stream <NUM> because it follows a shorter path from the base station <NUM> to the UE <NUM>.

As noted above, the beam of interest for data communication between a base station (e.g., base station <NUM>) and a UE (e.g., UE <NUM>) is the beam carrying RF signals that arrives at the UE with the highest signal strength (e.g., highest RSRP or SINR), whereas the beam of interest for position estimation is the beam carrying RF signals that excite the LOS path and that has the highest gain along the LOS path amongst all other beams (e.g., beam <NUM>). That is, even if beam <NUM> (the NLOS beam) were to weakly excite the LOS path (due to the propagation characteristics of RF signals, even though not being focused along the LOS path), that weak signal, if any, of the LOS path of beam <NUM> may not be as reliably detectable (compared to that from beam <NUM>), thus leading to greater error in performing a positioning measurement.

While the beam of interest for data communication and the beam of interest for position estimation may be the same beams for some frequency bands, for other frequency bands, such as mmW, they may not be the same beams. As such, referring to <FIG>, where the UE <NUM> is engaged in a data communication session with the base station <NUM> (e.g., where the base station <NUM> is the serving base station for the UE <NUM>) and not simply attempting to measure reference RF signals transmitted by the base station <NUM>, the beam of interest for the data communication session may be the beam <NUM>, as it is carrying the unobstructed NLOS data stream <NUM>. The beam of interest for position estimation, however, would be the beam <NUM>, as it carries the strongest LOS data stream <NUM>, despite being obstructed.

<FIG> is a graph 600A showing the RF channel response at a receiver (e.g., UE <NUM>) over time according to aspects of the disclosure. Under the channel illustrated in <FIG>, the receiver receives a first cluster of two RF signals on channel taps at time T1, a second cluster of five RF signals on channel taps at time T2, a third cluster of five RF signals on channel taps at time T3, and a fourth cluster of four RF signals on channel taps at time T4. In the example of <FIG>, because the first cluster of RF signals at time T1 arrives first, it is presumed to be the LOS data stream (i.e., the data stream arriving over the LOS or the shortest path), and may correspond to the LOS data stream <NUM>. The third cluster at time T3 is comprised of the strongest RF signals, and may correspond to the NLOS data stream <NUM>. Seen from the transmitter's side, each cluster of received RF signals may comprise the portion of an RF signal transmitted at a different angle, and thus each cluster may be said to have a different angle of departure (AoD) from the transmitter. <FIG> is a diagram 600B illustrating this separation of clusters in AoD. The RF signal transmitted in AoD range 602a may correspond to one cluster (e.g., "Cluster1") in <FIG>, and the RF signal transmitted in AoD range 602b may correspond to a different cluster (e.g., "Cluster3") in <FIG>. Note that although AoD ranges of the two clusters depicted in <FIG> are spatially isolated, AoD ranges of some clusters may also partially overlap even though the clusters are separated in time. For example, this may arise when two separate buildings at same AoD from the transmitter reflect the signal towards the receiver. Note that although <FIG> illustrates clusters of two to five channel taps, as will be appreciated, the clusters may have more or fewer than the illustrated number of channel taps.

As in the example of <FIG>, the base station may utilize beamforming to transmit a plurality of beams of RF signals such that one of the beams (e.g., beam <NUM>) is directed at the AoD range 602a of the first cluster of RF signals, and a different beam (e.g., beam <NUM>) is directed at the AoD range 602b of the third cluster of RF signals. The signal strength of clusters in post-beamforming channel response (i.e., the channel response when the transmitted RF signal is beamformed instead of omni-directional) will be scaled by the beam gain along the AoD of the clusters. In that case, the beam of interest for positioning would be the beam directed at the AoD of the first cluster of RF signals, as they arrive first, and the beam of interest for data communications may be the beam directed at the AoD of the third cluster of RF signals, as they are the strongest.

In general, when transmitting an RF signal, the transmitter does not know what path it will follow to the receiver (e.g., UE <NUM>) or at what time it will arrive at the receiver, and therefore transmits the RF signal on different antenna ports with an equal amount of energy. Alternatively, the transmitter may beamform the RF signal in different directions over multiple transmission occasions and obtain measurement feedback from the receiver to explicitly or implicitly determine radio paths.

Note that although the techniques disclosed herein have generally been described in terms of transmissions from a base station to a UE, as will be appreciated, they are equally applicable to transmissions from a UE to a base station where the UE is capable of MIMO operation and/or beamforming. Also, while beamforming is generally described above in context with transmit beamforming, receive beamforming may also be used in conjunction with the above-noted transmit beamforming in certain embodiments.

As discussed above, in some frequency bands, the shortest path (which may, as noted above, be a LOS path or the shortest NLOS path) may be weaker than an alternative longer (NLOS) path (over which the RF signal arrives later due to propagation delay). Thus, where a transmitter uses beamforming to transmit RF signals, the beam of interest for data communication - the beam carrying the strongest RF signals - may be different from the beam of interest for position estimation - the beam carrying the RF signals that excite the shortest detectable path. As such, it would be beneficial for the receiver to identify and report the beam of interest for position estimation to the transmitter to enable the transmitter to subsequently modify the set of transmitted beams to assist the receiver to perform a position estimation.

<FIG> illustrates an exemplary method according to an aspect of the disclosure. At <NUM>, a second node <NUM> (referred to as the "transmitter") transmits a set of beams <NUM>, <NUM>, and <NUM> to a first node <NUM> (referred to as the "receiver"). In an aspect, the first node <NUM> may be a UE, such as UE <NUM>/<NUM>/<NUM>, and the second node <NUM> may be a base station, such as base station <NUM>/<NUM>/<NUM>. However, in an aspect, the first node <NUM> may be a base station and the second node <NUM> may be a UE, or both the first node <NUM> and the second node <NUM> may be UEs or base stations. As yet another alternative, the second node <NUM> may be a single antenna or antenna array of a base station or UE capable of beamforming.

In the example of <FIG>, the second node <NUM> transmits a set of three beams <NUM>, <NUM>, and <NUM>. These beams may be transmitted simultaneously but distinguishable in frequency and/or code domain. Alternatively, these beams may be transmitted sequentially. The second node <NUM> may transmit the beams <NUM>, <NUM>, and <NUM> at different AoDs, as illustrated above in <FIG> and <FIG>. In the example of <FIG>, the beam <NUM> (illustrated as a straight line) may follow the shortest path (e.g., LOS path or shortest NLOS path when the LOS path is undetectable due to obstruction) from the second node <NUM> to the first node <NUM>, and the beams <NUM> and <NUM> may follow longer (e.g., NLOS) paths from the second node <NUM> to the first node <NUM>. As will be appreciated, there may be more or fewer than three beams, as shown above in the examples of <FIG> and <FIG>. In an aspect, the beams <NUM>, <NUM>, and <NUM> may carry synchronization signals, such as Synchronization Signal (SS) or PBCH blocks, CSI reference signals, positioning reference signals, cell reference signals, sounding reference signals, random access preamble, or the like.

At <NUM>, the first node <NUM> receives the beams <NUM>, <NUM>, and <NUM>. At <NUM>, the first node <NUM> determines the time of arrival of each beam <NUM>, <NUM>, and <NUM>. In an aspect, the first node <NUM> may determine the time of arrival of a beam as the time at which the first node <NUM> detects the first (or earliest) channel tap of the radio channel between the nodes, where the channel is estimated from the received RF signal of a beam <NUM>, <NUM>, or <NUM>. For example, the first node <NUM> may correlate the received signal of a beam with the (conjugate of) known transmitted RF signals and determine the channel taps from the peaks of correlation. The first node <NUM> may further estimate noise and eliminate channel taps that are less reliable for being comparable to a noise floor. The first node <NUM> may further employ techniques to eliminate spurious side peaks around strong channel taps, where the spurious side peaks are well known to arise from bandlimited reception at the first node <NUM>. For simplicity, the first channel tap of an RF signal of a beam may also be referred to as the first channel tap of a beam.

At <NUM>, the first node <NUM> identifies one or more beams of interest from the set of beams <NUM>, <NUM>, and <NUM> based on the times of arrival determined at <NUM>. As noted above, in some frequency bands where typically deployed antenna systems do not create narrow enough beams, the beam(s) of interest would be the beam(s) <NUM>, <NUM>, and/or <NUM> carrying RF signals with the highest received signal strength at the first node <NUM> (e.g., RSRP or SINR), as these would also be the beam(s) following the shortest path to the first node <NUM>. However, as discussed above, in some frequency bands, such as mmW, the beam carrying RF signals with the highest received signal strength may not be the best beam for positioning operations as it may not follow the shortest detectable path to the first node <NUM>. As such, rather than select the beam(s) carrying RF signals with the highest received signal strength, the first node <NUM> instead identifies one or more of the earliest arriving beams of the beams <NUM>, <NUM>, and <NUM> as the one or more beams of interest. For example, the one or more beams of interest may be the beam <NUM>, <NUM>, or <NUM> with the first detected channel tap. Or the one or more beams of interest may be the N (greater than <NUM>, e.g., <NUM>) beams with the earliest detected channel taps. Or the one or more beams of interest may be the beam, or N beams, whose first detected channel tap is within a predetermined delay (e.g., <NUM> nanoseconds) from the first detected tap of the beam with the earliest detected first tap. At the speed of light of about <NUM> meters per nanosecond (ns), an error or ambiguity of 10ns in time of arrival corresponds to a positioning/distancing error of approximately three meters. Therefore, the delay may be determined by the desired accuracy or achievable accuracy in the presence of other limiting factors, such as signal pulse width (related to signal bandwidth). The delay parameter may be provided to the second node <NUM> by the first node <NUM>, or determined by the first node <NUM> itself and reported to the second node <NUM>. In an aspect, where the first node <NUM> is a UE, the second node <NUM> (a base station) may command the first node <NUM> to report the beams of interest for position estimation (instead of the beams with the highest received signal strength, as is conventionally done), the number N of beams to report, and/or the "delay" parameter for selecting N beams.

At <NUM>, the first node <NUM> generates a report containing identifiers (e.g., beam indices) of the one or more beams of interest identified at <NUM>. At <NUM>, the first node <NUM> transmits the report to the second node <NUM>.

At <NUM>, the second node <NUM> receives the report. The first node <NUM> may transmit at <NUM>, and the second node <NUM> may receive at <NUM>, the report over a wireless interface, such as a communication link <NUM> in <FIG>. The reception point of the second node <NUM> that receives the report may or may not be collocated with the transmission point(s) of second node <NUM> from which the beams <NUM>, <NUM>, <NUM> are transmitted. For example, the reception point of the second node <NUM> that receives the report may be assigned a different cell identity than that of the transmission point of the node that transmits the beams. The reception point may be the serving cell and the transmission point may be a non-serving cell, such as a neighbor cell.

At <NUM>, the second node <NUM> can select a second set of beams for transmission based on the received report. For example, where the first node <NUM> is attempting to perform a position estimation and the identified beam(s) are cell synchronization beam(s), the second node <NUM> can update the beam(s) identified in the report to transmit positioning RF signals, such as PRS or CSI-RS. Generally, beams transmitting synchronization signals are broader (less focused) than beams transmitting reference RF signals (e.g., CSI-RS). As such, in an aspect, the second node <NUM> may also transmit one or more finer (more focused) beams around the beam(s) identified in the report, after they have been modified to transmit reference RF signals. More specifically, the second node <NUM> may narrow the focus of the identified beam(s) and transmit one or more additional narrowly focused beams in the direction of the identified beam(s).

As another example, again where the first node <NUM> is attempting to perform a position estimation and the identified beam(s) are cell synchronization beam(s), the second node <NUM> can transmit one or more beams carrying positioning RF signals in the direction of the beam(s) identified in the report, without modifying the beam(s) identified in the report. Thus, in an aspect, the transmission of beams <NUM>, <NUM>, and <NUM> at <NUM> may be periodic (e.g., a broadcast for the benefit of all UEs served by the second node, where the second node is a base station), and the selection of beams at <NUM> may be for the transmission of specific positioning beacons for the benefit of the first node only, and may be transmitted at a different periodicity or aperiodically.

In an aspect, where the first node <NUM> is a base station, then reporting the beam indices at <NUM> and <NUM> means that the first node <NUM> asks the second node <NUM> (the UE) to transmit further reference beams based on the report. For example, the request may be to transmit the reported beams again, or to transmit finer beams around the reported beams. Thus, the operation at <NUM> is a way to shortlist the beam(s) of interest and subsequently to use the shortlisted beam(s) for on-going position estimation while discarding the 'uninteresting' beams.

At <NUM>, the second node <NUM> transmits the second set of beams, here, beams <NUM> and <NUM>. As discussed above, the beams <NUM> and <NUM> may correspond to two of the beams <NUM>, <NUM>, and <NUM> (where the report received at <NUM> identifies two of beams <NUM>, <NUM>, and <NUM>), but modified to transmit reference RF signals (e.g., PRS, CRS). Alternatively, beams <NUM> and <NUM> may correspond to one of beams <NUM>, <NUM>, and <NUM> modified to transmit reference RF signals, and an additional beam transmitting reference RF signals in the direction of the beams identified in the report received at <NUM>. In yet another aspect, beams <NUM> and <NUM> may be two new beams transmitting reference RF signals in the direction of the beams identified in the report received at <NUM>. In an aspect, although not illustrated, prior to transmitting the beams <NUM> and <NUM>, the second node <NUM> may transmit an indication of which beams it has selected for transmission at <NUM>.

In the example of <FIG>, there are two beams (<NUM> and <NUM>) transmitted at <NUM>. However, as will be appreciated, this is merely an example, and there may be more or fewer beams transmitted at <NUM>. In addition, in <FIG>, beam <NUM> is illustrated as following a LOS path and beam <NUM> is illustrated as following an NLOS path (i.e., as reflected off an object). However, as will be appreciated, both beams <NUM> and <NUM> may follow a LOS path, or both may be reflected.

At <NUM>, the first node <NUM> receives the beams <NUM> and <NUM>. The first node <NUM> may perform the process of <FIG> with a plurality of second nodes, including the second node <NUM>, in order to receive a sufficient number of shortest path beams that can be accurately measured to calculate, or assist the calculation of, a position estimate. For example, to perform a single OTDOA measurement, the first node <NUM> needs to measure reference RF signals from at least two second nodes. The first node <NUM> may make multiple OTDOA measurements to improve accuracy of a position estimate of the first node <NUM>.

<FIG> illustrates a method according to the claimed invention <NUM> for determining a position estimate of a UE in accordance with an embodiment of the disclosure. The method <NUM> may be performed by a UE <NUM>, which may correspond to any one of UEs <NUM>, <NUM> or <NUM> as described above with respect to <FIG>.

Referring to <FIG>, at <NUM>, the UE <NUM> (e.g., antenna(s) <NUM>, receiver(s) <NUM>, and/or RX processor <NUM>) receives, from a network entity, at least one base station almanac (BSA) message that indicates (i) a set of transmission point locations associated with at least one base station, the set of transmission point locations including at least one transmission point location of a base station that is based upon a plurality of different transmission point locations associated with the base station, and (ii) a mapping of each of a plurality of beams to the at least one transmission point location. In an example, the network component from which the at least one BSA message is received corresponds to the base station itself. In an alternative example, the at least one BSA message may be received from a server, such as the location server <NUM>, although the base station may facilitate the wireless transmission of the at least one BSA message even if the base station does not act as the originating source of the at least one BSA message.

<FIG> illustrates an arrangement <NUM> of beams being transmitted by a base station (BS<NUM>) in accordance with aspects of the disclosure. In <FIG>, the base station is provisioned with three distinct transmission point locations denoted as A, B and C, which are connected to each other via a backhaul link. In particular, the transmission point locations A, B and C correspond to different antennas (or antenna arrays) through which the base station can transmit beams of RF signals. These respective antennas may be referred to as remote radio heads (RRHs) or remote radio units (RRUs). In the embodiment of <FIG>, the base station collectively transmits eight (<NUM>) total beams indexed with beam indices <NUM>. <NUM> from transmission point locations A, B and C, as follows:.

The information noted above in Table <NUM> may be determined in advance and stored in a BSA database (more specifically, in a BSA record for the base station), which is accessible to the network entity via a lookup operation.

Turning back to <NUM> of <FIG>, in an example, the at least one BSA message may convey some or all of the information contained in Table <NUM>. In a first example, the at least one BSA message may indicate the specific locations of each of the transmission point locations A, B and C along with the associated beams being transmitted at each transmission point location. In a second example, instead of each beam being individually mapped to a particular transmission point location, the beams may instead be mapped to a representative single representative transmission point location that is based upon the transmission point locations A, B and C. This representative single representative transmission point location may be denoted as transmission point location A+B+C. For example, the transmission point location A+B+C may be averaged (e.g., weighted average, etc.) in some manner from the different transmission point locations A, B and C. In an alternative example, the transmission point location A+B+C may correspond to one of the different transmission point locations A, B and C. An example mapping of beams <NUM>. <NUM> in <FIG> to transmission point locations A, B and C is as follows:.

In a third example, instead of a single representative transmission point location being used for all beams transmitted by a particular base station, representative transmission point locations may be used for particular subsets of beams. For example, certain beams with the same beam index may be transmitted from different transmission point locations. In terms of beam mapping, the UE can be notified of each transmission point location to which this beam is mapped, or to a representative transmission point location based on the transmission point locations. Consider a scenario as shown in Table <NUM> above, except the beam with beam index <NUM> is transmitted from both A and B, and the beam with beam index <NUM> is transmitted from both B and C, and shown in Table <NUM>:.

In this case, the BSA message can be configured to notify the UE that beam index <NUM> is transmitted from both A and B by indicating both transmission point locations, or alternatively can identify a location that approximates (e.g., averages) the transmission point locations of A and B. Likewise, the BSA message can be configured to notify the UE that beam index <NUM> is transmitted from both B and C by indicating both transmission point locations, or alternatively can identify a location that approximates (e.g., averages) the transmission point locations of B and C. The information noted above in Table <NUM> may be determined in advance and stored in a BSA database (more specifically, in a BSA record for the base station), which is accessible to the network entity via a lookup operation.

Referring to <FIG>, at <NUM>, at the UE <NUM> (e.g., antenna(s) <NUM>, receiver(s) <NUM>, and/or RX processor <NUM>) receives, from the base station, the plurality of beams in accordance with the mapping. At <NUM>, the UE <NUM> (e.g., controller/processor <NUM>) estimates a position of the UE based at least in part upon (i) one or more measurements performed by the UE on one or more of the plurality of beams and (ii) the at least one transmission point location to which the one or more beams are mapped.

Referring to <NUM> of <FIG>, in an example, the plurality of beams received at the UE <NUM> may carry synchronization signal blocks (SSBs). In an example specific to <NUM> NR, SSBs may be transmitted using up to <NUM> different transmission beams or transmission precoders, so a number of different cells and/or transmission point locations can use SSBs as positioning beacons without a conflict. Other beamswept signals that can be used as positioning signals may include reference signals (RSs), such as a PRS, a UE-specific or cell-specific CSI-RS, and so on.

In an example, the one or more measurements used to estimate the UE position at <NUM> may correspond to Time of Arrival (ToA) measurements. The ToA measurements may be used to compute OTDOA between ToA of beams transmitted from different transmission locations, where the OTDOA measurements are subsequently used to derive the UE position estimate. Similarly, the ToA measurements may be used as part of round trip propagation time (RTT) estimation procedure(s) between the UE <NUM> and the transmission location points of the base station, after which the calculated RTT(s) are used to derive the UE position estimate (e.g., via multilateration, such as trilateration). For example, if the at least one transmission location point used at <NUM> is the plurality of different transmission location points, the UE determines a mapping of each beam to a respective transmission location point based on the at least one BSA message, and then derives a different RTT to each transmission location point based on the associated ToA measurements for that transmission location point's mapped beam(s). UE may not compute a ToA for a transmission location point from which the UE does not detect a beam (or does not detect the beam reliably enough) for estimating ToA. In another example, if the at least one transmission location point used at <NUM> is the single representative transmission location point, the UE derives a single RTT to the single representative transmission location point based on the associated ToA measurements for the plurality of beams (e.g., as if each beam was transmitted from the single representative transmission location point, irrespective of which transmission location point the beams were actually transmitted from).

Referring to <NUM> of <FIG>, in a further example, assume that the UE <NUM> cannot ascertain the transmission point location to which a particular beam or group of beams is mapped. In this case, the UE <NUM> may determine multiple candidate transmission point locations to which at least one of the one or more beams is mapped. For example, as noted above with respect to Table <NUM>, the UE <NUM> may be notified via the BSA message(s) that a particular beam is being transmitted from multiple transmission point locations. The UE <NUM> may then estimate multiple candidate position estimates of the UE <NUM> at <NUM> based on the multiple candidate transmission point locations. For example, the UE <NUM> may select one transmission point location from the multiple candidate transmission point locations, and assume that the detected ToA is based on the signal received from the selected transmission point location. That is, in the multilateration procedure, the location of the selected transmission point is used as the only transmission location of the signal and a candidate position of the UE <NUM> estimated under this assumption. In this manner, the UE <NUM> can calculate a candidate position estimate corresponding to each candidate transmission point location. The UE <NUM> may then derive the position estimate for the UE based on the multiple candidate position estimates. For example, the position estimate derivation may include (i) averaging of the multiple candidate position estimates, or (ii) selecting the candidate position estimate that is most congruent with one or more other positioning measurements such as ToA measurements from other known transmission locations and previously estimated position estimates for the UE. For example, the most congruent candidate position estimate may correspond to the position estimate that is geographically closest to one or more previous position estimates for the UE, the position estimate that tracks closest to a trajectory at which the UE has been logged as moving, and so on. Similarly, the UE <NUM> may employ statistical techniques for outlier elimination such as RANSAC algorithm to eliminate false hypotheses on the candidate transmission point locations when a beam is transmitted from multiple transmission points locations.

<FIG> illustrates a method according to the claimed invention <NUM> for transmitting location information pertaining to a plurality of different transmission point locations associated with a base station in accordance with an embodiment of the disclosure. The method <NUM> may be performed by a network entity <NUM>, which may correspond to a base station such as any of base stations <NUM>, <NUM>, <NUM>, <NUM>, 402a-402d, <NUM>, or alternatively to a server such as <NUM> or 300B.

Referring to <FIG>, at <NUM>, the network entity <NUM> (e.g., antenna(s) <NUM>, transmitter(s) <NUM>, and/or TX processor <NUM>, network access ports 304B) transmits, to a UE, at least one BSA message that indicates (i) a set of transmission point locations associated with at least one base station, the set of transmission point locations including at least one transmission point location of a base station that is based upon a plurality of different transmission point locations associated with the base station, and (ii) a mapping of each of a plurality of beams to the at least one transmission point location. In an example, the at least one BSA message transmitted at <NUM> corresponds to the at least one BSA message received by the UE <NUM> at <NUM> of <FIG>.

Referring to <FIG>, at <NUM>, the network entity <NUM> (e.g., antenna(s) <NUM>, transmitter(s) <NUM>, and/or TX processor <NUM>) optionally transmits the plurality of beams from the at least one transmission point location of the base station in accordance with the mapping. The transmission at <NUM> may be performed by the network entity <NUM> if the network entity <NUM> corresponds to the base station. However, as noted above, the network entity <NUM> could also correspond to a server that is separate from the base station transmitting the beams, in which case <NUM> is not performed by the network entity <NUM>. In an example, the beams that are optionally transmitted by the network entity <NUM> at <NUM> correspond to the beams received by the UE <NUM> at <NUM> of <FIG>.

<FIG> illustrate example implementations of the processes of <FIG> and <FIG> in accordance with embodiments of the disclosure.

Referring to <FIG>, assume that <NUM>-<NUM> of <FIG> are performed. After <NUM> of <FIG>, at <NUM>, the UE <NUM> transmits, to the network entity <NUM>, a request for location information related to the base station along with an indication of the identified beam(s) of interest from <NUM>. The network entity <NUM> receives the request at <NUM>. At <NUM>, the network entity <NUM> transmits at least one BSA message including transmission point location(s) that are mapped to the identified beam(s) of interest, along with the associated mapping information. At <NUM>, the UE <NUM> receives the at least one BSA message. The BSA message(s) exchanged at <NUM>-<NUM> may correspond to the BSA message(s) exchanged at <NUM> of <FIG> or <NUM> of <FIG>. So, the process of <FIG> demonstrates that the BSA message(s) may be exchanged responsive to a request from the UE <NUM>, in particular, a request that is both base station-specific and beam-specific.

In other embodiments, the UE <NUM> need not specify any particular beam(s) of interest as in <FIG>. Rather, the UE <NUM> need only identify the base station for which location information is needed, and the network entity <NUM> can send BSA message(s) that convey all the transmission point location(s) that are mapped to any beam being transmitted by that base station, along with the associated mapping information. Moreover, the network entity <NUM> may send transmission point location information for one or more other base stations as well, either in the same BSA message(s) or in different BSA message(s).

Referring to <FIG>, assume that <NUM>-<NUM> of <FIG> are performed. After <NUM> of <FIG>, at <NUM>, the base station (denoted as base station <NUM> in <FIG>) transmits, to the UE <NUM>, a set of beams including beams <NUM>, <NUM> and <NUM> in accordance with the mapping that is conveyed by the BSA message(s) from <NUM>-<NUM>. The set of beams is received by the UE <NUM> at <NUM>. The beams exchanged at <NUM>-<NUM> may correspond to the beams exchanged at <NUM> of <FIG> or <NUM> of <FIG>. At <NUM>, the UE <NUM> estimates its position based on measurement(s) performed by the UE <NUM> on one or more beams from the set of beams as well as the at least one transmission point location (e.g., a plurality of different beam-mapped transmission point locations or a single representative transmission point location for the base station as noted above).

Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques.

Further, those skilled in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted to depart from the scope of the various aspects described herein.

The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or other such configurations).

The methods, sequences, and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of non-transitory computer-readable medium known in the art. An exemplary non-transitory computer-readable medium may be coupled to the processor such that the processor can read information from, and write information to, the non-transitory computer-readable medium. In the alternative, the non-transitory computer-readable medium may be integral to the processor. The processor and the non-transitory computer-readable medium may reside in an ASIC. The ASIC may reside in a user device (e.g., a UE) or a base station. In the alternative, the processor and the non-transitory computer-readable medium may be discrete components in a user device or base station.

In one or more exemplary aspects, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Computer-readable media may include storage media and/or communication media including any non-transitory medium that may facilitate transferring a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. The term disk and disc, which may be used interchangeably herein, includes CD, laser disc, optical disc, DVD, floppy disk, and Blu-ray discs, which usually reproduce data magnetically and/or optically with lasers.

Claim 1:
A method (<NUM>) of operating a user equipment, UE, comprising:
receiving (<NUM>), from a network entity, at least one base station almanac, BSA, message that indicates (i) a set of antenna locations associated with at least one base station, the set of antenna locations including at least one antenna location of a base station that is based upon a plurality of different antenna locations associated with the base station, the at least one antenna location including a single antenna location that is representative of multiple different antenna locations of the base station, and (ii) a mapping of each of a plurality of beams to the at least one antenna location;
receiving (<NUM>), from the base station, the plurality of beams in accordance with the mapping; and
performing one or more measurements on one or more of the plurality of beams.