Patent Description:
Aspects of the disclosure relate generally to wireless communications and more particularly to reference device (e.g., base station or reference user equipment (UE)) hardware group delay.

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> networks), a third-generation (<NUM>) high speed data, Internet-capable wireless service and a fourth-generation (<NUM>) service (e.g., 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>) wireless standard, referred to as New Radio (NR), enables 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 wireless 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. <CIT> discloses techniques for determining a position of a user equipment (UE). A differential round-trip-time (RTT) based positioning procedure is proposed to determine the UE position. In this technique, the UE position is determined based on the differences of the RTTs between the UE and a plurality of base stations. The differential RTT based positioning procedure has much looser inter-gNodeB timing synchronization requirements than the OTDOA technique and also has much looser group delay requirements than traditional RTT procedures.

The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.

In an aspect, a method of operating a communications node includes obtaining a hardware group delay calibration capability associated with each of a plurality of reference devices; selecting a reference device from among the plurality of reference devices based at least on the hardware group delay calibration capabilities associated with the plurality of reference devices; and determining one or more timing measurements associated with each of the plurality of reference devices based on a reference hardware group delay calibration value associated with the selected reference device.

The plurality of reference devices comprise at least one base station, at least one reference UE, or a combination thereof.

The method includes transmitting a hardware group delay calibration capability request to each of the plurality of reference devices, wherein the obtaining comprises receiving the hardware group delay calibration capability for each of the plurality of reference devices in response to the request.

In some aspects, the determination is performed in association with a positioning procedure for a user equipment (UE).

In some aspects, the communications node corresponds to the UE, and the positioning procedure is a UE-based positioning procedure.

In some aspects, the communications node corresponds to a network device, and the positioning procedure is a network-based positioning procedure.

In some aspects, the positioning procedure corresponds to a round trip time (RTT) positioning procedure.

In some aspects, the positioning procedure corresponds to a differential RTT positioning procedure or a double differential RTT positioning procedure.

In some aspects, the positioning procedure corresponds to a time difference of arrival (TDOA)-based positioning procedure.

In some aspects, the determination is performed independent of any UE positioning procedure.

In some aspects, the hardware group delay calibration capabilities for each of the plurality of reference devices indicates a respective hardware group delay error range.

In some aspects, the selecting selects the selected reference device as the reference device associated with the narrowest hardware group delay error range.

In some aspects, the selecting selects the selected reference device based on the hardware group delay calibration capabilities associated with the plurality of reference devices and at least one secondary criteria.

In some aspects, the at least one secondary criteria comprises reference signal received power (RSRP) measurements between the plurality of reference devices and a user equipment (UE).

In some aspects, the hardware group delay calibration capability for at least one of the plurality of reference devices is specific to a particular set of frequency-domain resources, a particular set of beams, a particular transmission reception point (TRP).

In some aspects, the hardware group delay calibration capability for at least one of the plurality of reference devices is time-varying, and the obtaining obtains at least one parameter for modeling a time-varying function of the hardware group delay calibration capability the at least one reference device.

In some aspects, the obtaining comprises receipt of differential hardware group delay calibration capability information that is relative to previously received hardware group delay calibration capability information.

In an aspect, a method of operating a communications node includes obtaining an estimated distance between a first reference device and a second reference device that is based on one or more timing measurements of one or more reference signals for positioning between the first and second reference devices; and estimating a hardware group delay associated with the first and second reference devices based on (i) the estimated distance between the first and second reference devices, and (ii) a known distance between the first and second reference devices.

In some aspects, the first and second reference devices comprise at least one base station, at least one reference user equipment (UE), or a combination thereof.

In some aspects, the communications node corresponds to one of the first and second reference devices, or the communications node corresponds to a network entity separate from the first and second reference devices.

In some aspects, the one or more timing measurements are associated with a round trip time (RTT) measurement or a time difference of arrival (TDOA) measurement.

In some aspects, the first reference device is associated with a reference hardware group delay.

In some aspects, the estimating estimates a residual hardware group delay that corresponds to a differential between a hardware group delay of the second reference device and the reference hardware group delay of the first reference device.

In an aspect, a communications node includes a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: obtain a hardware group delay calibration capability associated with each of a plurality of reference devices; select a reference device from among the plurality of reference devices based at least on the hardware group delay calibration capabilities associated with the plurality of reference devices; and determine one or more timing measurements associated with each of the plurality of reference devices based on a reference hardware group delay calibration value associated with the selected reference device.

The at least one processor is further configured to: transmit, via the at least one transceiver, a hardware group delay calibration capability request to each of the plurality of reference devices, wherein the obtaining comprises receiving the hardware group delay calibration capability for each of the plurality of reference devices in response to the request.

In an aspect, a communications node includes a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: obtain an estimated distance between a first reference device and a second reference device that is based on one or more timing measurements of one or more reference signals for positioning between the first and second reference devices; and estimate a hardware group delay associated with the first and second reference devices based on (i) the estimated distance between the first and second reference devices, and (ii) a known distance between the first and second reference devices.

In an aspect, a communications node includes means for obtaining a hardware group delay calibration capability associated with each of a plurality of reference devices; means for selecting a reference device from among the plurality of reference devices based at least on the hardware group delay calibration capabilities associated with the plurality of reference devices; and means for determining one or more timing measurements associated with each of the plurality of reference devices based on a reference hardware group delay calibration value associated with the selected reference device.

In some aspects, the plurality of reference devices comprise at least one base station, at least one reference UE, or a combination thereof.

In some aspects, the method includes means for transmitting a hardware group delay calibration capability request to each of the plurality of reference devices, wherein the obtaining comprises receiving the hardware group delay calibration capability for each of the plurality of reference devices in response to the request.

In an aspect, a communications node includes means for obtaining an estimated distance between a first reference device and a second reference device that is based on one or more timing measurements of one or more reference signals for positioning between the first and second reference devices; and means for estimating a hardware group delay associated with the first and second reference devices based on (i) the estimated distance between the first and second reference devices, and (ii) a known distance between the first and second reference devices.

In an aspect, a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a communications node, cause the communications node to: obtain a hardware group delay calibration capability associated with each of a plurality of reference devices; select a reference device from among the plurality of reference devices based at least on the hardware group delay calibration capabilities associated with the plurality of reference devices; and determine one or more timing measurements associated with each of the plurality of reference devices based on a reference hardware group delay calibration value associated with the selected reference device.

In some aspects, the one or more instructions further cause the communications node to: transmit a hardware group delay calibration capability request to each of the plurality of reference devices, wherein the obtaining comprises receiving the hardware group delay calibration capability for each of the plurality of reference devices in response to the request.

In an aspect, a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a communications node, cause the communications node to: obtain an estimated distance between a first reference device and a second reference device that is based on one or more timing measurements of one or more reference signals for positioning between the first and second reference devices; and estimate a hardware group delay associated with the first and second reference devices based on (i) the estimated distance between the first and second reference devices, and (ii) a known distance between the first and second reference devices.

As used herein, the terms "user equipment" (UE) and "base station" are not intended to be specific or otherwise limited to any particular Radio Access Technology (RAT), unless otherwise noted. In general, a UE may be any wireless communication device (e.g., a mobile phone, router, tablet computer, laptop computer, tracking device, wearable (e.g., smartwatch, glasses, augmented reality (AR) / virtual reality (VR) headset, etc.), vehicle (e.g., automobile, motorcycle, bicycle, etc.), 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, wireless local area network (WLAN) networks (e.g., based on IEEE <NUM>, 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 New Radio (NR) Node B (also referred to as a gNB or gNodeB), 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. A communication link through which UEs can send signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the base station can send signals to UEs is called a downlink (DL) 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 UL / reverse or DL / forward traffic channel.

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 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 multiple-input multiple-output (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 and a neighbor base station whose reference RF signals the UE is measuring.

An "RF signal" comprises an electromagnetic wave of a given frequency that transports information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels. The same transmitted RF signal on different paths between the transmitter and receiver may be referred to as a "multipath" RF signal.

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 cell base stations (high power cellular base stations) and/or small cell base stations (low power cellular base stations). In an aspect, the macro cell base station may include eNBs where the wireless communications system <NUM> corresponds to an LTE network, or gNBs where the wireless communications system <NUM> corresponds to a <NUM> network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc..

The base stations <NUM> may collectively form a RAN and interface with a core network <NUM> (e.g., an evolved packet core (EPC) or next generation core (NGC)) through backhaul links <NUM>, and through the core network <NUM> to one or more location servers <NUM>. 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, one or more cells may be supported by a base station <NUM> in each coverage area <NUM>. A "cell" is a logical communication entity used for communication with a base station (e.g., over some frequency resource, referred to as a carrier frequency, component carrier, carrier, band, or the like), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) for distinguishing cells operating via the same or a different carrier frequency. In some cases, different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of UEs. In some cases, the term "cell" may also refer to a geographic coverage area of a base station (e.g., a sector), insofar as a carrier frequency can be detected and used for communication within some portion of geographic coverage areas <NUM>.

While neighboring macro cell base station <NUM> 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 coverage area <NUM>' that substantially overlaps with the coverage area <NUM> of one or more macro cell base stations <NUM>. A network that includes both small cell and macro cell base stations 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> between the base stations <NUM> and the UEs <NUM> may include UL (also referred to as reverse link) transmissions from a UE <NUM> to a base station <NUM> and/or downlink (DL) (also referred to as forward link) transmissions from a base station <NUM> to a UE <NUM>. 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 carrier frequencies. 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.

Receive beams may be spatially related. A spatial relation means that parameters for a transmit beam for a second reference signal can be derived from information about a receive beam for a first reference signal. For example, a UE may use a particular receive beam to receive a reference downlink reference signal (e.g., synchronization signal block (SSB)) from a base station. The UE can then form a transmit beam for sending an uplink reference signal (e.g., sounding reference signal (SRS)) to that base station based on the parameters of the receive beam.

In <NUM>, the frequency spectrum in which wireless nodes (e.g., base stations <NUM>/<NUM>, UEs <NUM>/<NUM>) operate is divided into multiple frequency ranges, FR1 (from <NUM> to <NUM>), FR2 (from <NUM> to <NUM>), FR3 (above <NUM>), and FR4 (between FR1 and FR2). In a multi-carrier system, such as <NUM>, one of the carrier frequencies is referred to as the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell," and the remaining carrier frequencies are referred to as "secondary carriers" or "secondary serving cells" or "SCells. " In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) utilized by a UE <NUM>/<NUM> and the cell in which the UE <NUM>/<NUM> either performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection reestablishment procedure. The primary carrier carries all common and UE-specific control channels. A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once the RRC connection is established between the UE <NUM> and the anchor carrier and that may be used to provide additional radio resources. The secondary carrier may contain only necessary signaling information and signals, for example, those that are UE-specific may not be present in the secondary carrier, since both primary uplink and downlink carriers are typically UE-specific. This means that different UEs <NUM>/<NUM> in a cell may have different downlink primary carriers. The same is true for the uplink primary carriers. The network is able to change the primary carrier of any UE <NUM>/<NUM> at any time. This is done, for example, to balance the load on different carriers. Because a "serving cell" (whether a PCell or an SCell) corresponds to a carrier frequency / component carrier over which some base station is communicating, the term "cell," "serving cell," "component carrier," "carrier frequency," and the like can be used interchangeably.

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 example 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> and <NUM> may be supported with any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on.

The wireless communications system <NUM> may further include a UE <NUM> that may communicate with a macro cell base station <NUM> over a communication link <NUM> and/or the mmW base station <NUM> over a mmW communication link <NUM>. For example, the macro cell base station <NUM> may support a PCell and one or more SCells for the UE <NUM> and the mmW base station <NUM> may support one or more SCells for the UE <NUM>. In an aspect, the UE <NUM> may include a positioning component <NUM> that may enable the UE <NUM> to perform the UE operations described herein. Note that although only one UE in <FIG> is illustrated as having fully staggered SRS component <NUM>, any of the UEs in <FIG> may be configured to perform the UE operations described herein.

According to various aspects, <FIG> illustrates an example wireless network structure <NUM>. For example, an NGC <NUM> (also referred to as a "5GC") 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>. 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>). 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 separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), 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, an NGC <NUM> (also referred to as a "5GC") can be viewed functionally as control plane functions, provided by an access and mobility management function (AMF) / user plane function (UPF) <NUM>, and user plane functions, provided by a session management function (SMF) <NUM>, which operate cooperatively to form the core network (i.e., NGC <NUM>). User plane interface <NUM> and control plane interface <NUM> connect the eNB <NUM> to the NGC <NUM> and specifically to SMF <NUM> and AMF/UPF <NUM>, respectively. In an additional configuration, a gNB <NUM> may also be connected to the NGC <NUM> via control plane interface <NUM> to AMF/UPF <NUM> and user plane interface <NUM> to SMF <NUM>. Further, eNB <NUM> may directly communicate with gNB <NUM> via the backhaul connection <NUM>, with or without gNB direct connectivity to the NGC <NUM>. 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>). The base stations of the New RAN <NUM> communicate with the AMF-side of the AMF/UPF <NUM> over the N2 interface and the UPF-side of the AMF/UPF <NUM> over the N3 interface.

The functions of the AMF include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between the UE <NUM> and the SMF <NUM>, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE <NUM> and the short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF also interacts with the authentication server function (AUSF) (not shown) and the UE <NUM>, and receives the intermediate key that was established as a result of the UE <NUM> authentication process. In the case of authentication based on a UMTS (universal mobile telecommunications system) subscriber identity module (USIM), the AMF retrieves the security material from the AUSF. The functions of the AMF also include security context management (SCM). The SCM receives a key from the SEAF that it uses to derive access-network specific keys. The functionality of the AMF also includes location services management for regulatory services, transport for location services messages between the UE <NUM> and the location management function (LMF) <NUM>, as well as between the New RAN <NUM> and the LMF <NUM>, evolved packet system (EPS) bearer identifier allocation for interworking with the EPS, and UE <NUM> mobility event notification. In addition, the AMF also supports functionalities for non-3GPP access networks.

Functions of the UPF include acting as an anchor point for intra-/inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point of interconnect to the data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., UL/DL rate enforcement, reflective QoS marking in the DL), UL traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in the UL and DL, DL packet buffering and DL data notification triggering, and sending and forwarding of one or more "end markers" to the source RAN node.

The functions of the SMF <NUM> include session management, UE Internet protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering at the UPF to route traffic to the proper destination, control of part of policy enforcement and QoS, and downlink data notification. The interface over which the SMF <NUM> communicates with the AMF-side of the AMF/UPF <NUM> is referred to as the N11 interface.

Another optional aspect may include a LMF <NUM>, which may be in communication with the NGC <NUM> to provide location assistance for UEs <NUM>. The LMF <NUM> can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The LMF <NUM> can be configured to support one or more location services for UEs <NUM> that can connect to the LMF <NUM> via the core network, NGC <NUM>, and/or via the Internet (not illustrated).

<FIG> illustrates several sample components (represented by corresponding blocks) that may be incorporated into a UE <NUM> (which may correspond to any of the UEs described herein), a base station <NUM> (which may correspond to any of the base stations described herein), and a network entity <NUM> (which may correspond to or embody any of the network functions described herein, including the location server <NUM> and the LMF <NUM>) to support the file transmission operations as taught herein. It will be appreciated that these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in a system may include components similar to those described to provide similar functionality. Also, a given apparatus may contain one or more of the components. For example, an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.

The UE <NUM> and the base station <NUM> each include at least one wireless communication device (represented by the communication devices <NUM> and <NUM> (and the communication device <NUM> if the apparatus <NUM> is a relay)) for communicating with other nodes via at least one designated RAT. For example, the communication devices <NUM> and <NUM> may communicate with each other over a wireless communication link <NUM>, which may correspond to a communication link <NUM> in <FIG>. Each communication device <NUM> includes at least one transmitter (represented by the transmitter <NUM>) for transmitting and encoding signals (e.g., messages, indications, information, and so on) and at least one receiver (represented by the receiver <NUM>) for receiving and decoding signals (e.g., messages, indications, information, pilots, and so on). Similarly, each communication device <NUM> includes at least one transmitter (represented by the transmitter <NUM>) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by the receiver <NUM>) for receiving signals (e.g., messages, indications, information, and so on). If the base station <NUM> is a relay station, each communication device <NUM> may include at least one transmitter (represented by the transmitter <NUM>) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by the receiver <NUM>) for receiving signals (e.g., messages, indications, information, and so on).

A transmitter and a receiver may comprise an integrated device (e.g., embodied as a transmitter circuit and a receiver circuit of a single communication device, generally referred to as a "transceiver") in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be embodied in other ways in other implementations. A wireless communication device (e.g., one of multiple wireless communication devices) of the base station <NUM> may also comprise a network listen module (NLM) or the like for performing various measurements.

The network entity <NUM> (and the base station <NUM> if it is not a relay station) includes at least one communication device (represented by the communication device <NUM> and, optionally, <NUM>) for communicating with other nodes. For example, the communication device <NUM> may comprise a network interface that is configured to communicate with one or more network entities via a wire-based or wireless backhaul <NUM> (which may correspond to the backhaul link <NUM> in <FIG>). In some aspects, the communication device <NUM> may be implemented as a transceiver configured to support wire-based or wireless signal communication, and the transmitter <NUM> and receiver <NUM> may be an integrated unit. This communication may involve, for example, sending and receiving: messages, parameters, or other types of information. Accordingly, in the example of <FIG>, the communication device <NUM> is shown as comprising a transmitter <NUM> and a receiver <NUM>. Alternatively, the transmitter <NUM> and receiver <NUM> may be separate devices within the communication device <NUM>. Similarly, if the base station <NUM> is not a relay station, the communication device <NUM> may comprise a network interface that is configured to communicate with one or more network entities <NUM> via a wire-based or wireless backhaul <NUM>. As with the communication device <NUM>, the communication device <NUM> is shown as comprising a transmitter <NUM> and a receiver <NUM>.

The apparatuses <NUM>, <NUM>, and <NUM> also include other components that may be used in conjunction with the file transmission operations as disclosed herein. The UE <NUM> includes a processing system <NUM> for providing functionality relating to, for example, the UE operations as described herein and for providing other processing functionality. The base station <NUM> includes a processing system <NUM> for providing functionality relating to, for example, the base station operations described herein and for providing other processing functionality. The network entity <NUM> includes a processing system <NUM> for providing functionality relating to, for example, the network function operations described herein and for providing other processing functionality. The apparatuses <NUM>, <NUM>, and <NUM> include memory components <NUM>, <NUM>, and <NUM> (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). In addition, the UE <NUM> includes a user interface <NUM> for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on). Although not shown, the apparatuses <NUM> and <NUM> may also include user interfaces.

Referring to the processing system <NUM> in more detail, in the downlink, IP packets from the network entity <NUM> may be provided to the processing system <NUM>. The processing system <NUM> may implement 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 processing system <NUM> may provide RRC layer functionality associated with broadcasting of system information (e.g., master information block (MIB), system information blocks (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 transmitter <NUM> and the receiver <NUM> may 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. The transmitter <NUM> handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. Each spatial stream may then be provided to one or more different antennas. The transmitter <NUM> may modulate an RF carrier with a respective spatial stream for transmission.

At the UE <NUM>, the receiver <NUM> receives a signal through its respective antenna(s). The receiver <NUM> recovers information modulated onto an RF carrier and provides the information to the processing system <NUM>. The transmitter <NUM> and the receiver <NUM> implement Layer-<NUM> functionality associated with various signal processing functions. The receiver <NUM> may perform spatial processing on the information to recover any spatial streams destined for the UE <NUM>. If multiple spatial streams are destined for the UE <NUM>, they may be combined by the receiver <NUM> into a single OFDM symbol stream. The receiver <NUM> then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT). These soft decisions may be based on channel estimates computed by a channel estimator. 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 processing system <NUM>, which implements Layer-<NUM> and Layer-<NUM> functionality.

In the UL, the processing system <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 processing system <NUM> is also responsible for error detection.

Similar to the functionality described in connection with the DL transmission by the base station <NUM>, the processing system <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 transport blocks (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 from a reference signal or feedback transmitted by the base station <NUM> may be used by the transmitter <NUM> to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the transmitter <NUM> may be provided to different antenna(s). The transmitter <NUM> may modulate an RF carrier with a respective spatial stream for transmission.

The receiver <NUM> receives a signal through its respective antenna(s). The receiver <NUM> recovers information modulated onto an RF carrier and provides the information to the processing system <NUM>.

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

In an aspect, the apparatuses <NUM>, <NUM> and <NUM> may include positioning components <NUM>, <NUM> and <NUM>, respectively. It will be appreciated the functionality of the various positioning components <NUM>, <NUM> and <NUM> may differ based on the device where it is being implemented. The positioning components <NUM>, <NUM> and <NUM> may be hardware circuits that are part of or coupled to the processing systems <NUM>, <NUM>, and <NUM>, respectively, that, when executed, cause the apparatuses <NUM>, <NUM>, and <NUM> to perform the functionality described herein. Alternatively, the positioning components <NUM>, <NUM> and <NUM> may be memory modules stored in the memory components <NUM>, <NUM>, and <NUM>, respectively, that, when executed by the processing systems <NUM>, <NUM>, and <NUM>, cause the apparatuses <NUM>, <NUM>, and <NUM> to perform the functionality described herein.

For convenience, the apparatuses <NUM>, <NUM>, and/or <NUM> are shown in <FIG> as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated blocks may have different functionality in different designs.

The various components of the apparatuses <NUM>, <NUM>, and <NUM> may communicate with each other over data buses <NUM>, <NUM>, and <NUM>, respectively. The components of <FIG> may be implemented in various ways. In some implementations, the components of <FIG> may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be implemented by processor and memory component(s) of the UE <NUM> (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Similarly, some or all of the functionality represented by blocks <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be implemented by processor and memory component(s) of the base station <NUM> (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Also, some or all of the functionality represented by blocks <NUM>, <NUM>, <NUM>, and <NUM> may be implemented by processor and memory component(s) of the network entity <NUM> (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). For simplicity, various operations, acts, and/or functions are described herein as being performed "by a UE," "by a base station," "by a positioning entity," etc. However, as will be appreciated, such operations, acts, and/or functions may actually be performed by specific components or combinations of components of the UE, base station, positioning entity, etc., such as the processing systems <NUM>, <NUM>, <NUM>, the communication devices <NUM>, <NUM>, <NUM>, positioning components <NUM>, <NUM> and <NUM>, etc..

Various frame structures may be used to support downlink and uplink transmissions between network nodes (e.g., base stations and UEs). <FIG> illustrates an example of a downlink frame structure <NUM> according to aspects of the disclosure. However, as those skilled in the art will readily appreciate, the frame structure for any particular application may be different depending on any number of factors. In <FIG>, time is represented horizontally (e.g., on the X axis) with time increasing from left to right, while frequency is represented vertically (e.g., on the Y axis) with frequency increasing (or decreasing) from bottom to top. In the time domain, a frame <NUM> (<NUM>) is divided into <NUM> equally sized subframes <NUM> (<NUM>). Each subframe <NUM> includes two consecutive time slots <NUM> (<NUM>).

A resource grid may be used to represent two time slots <NUM>, each time slot <NUM> including one or more resource blocks (RBs) <NUM> in the frequency domain (also referred to as "physical resource blocks" or "PRBs"). In LTE, and in some cases NR, a resource block <NUM> contains <NUM> consecutive subcarriers <NUM> in the frequency domain and, for a normal cyclic prefix (CP) in each OFDM symbol <NUM>, <NUM> consecutive OFDM symbols <NUM> in the time domain. A resource of one OFDM symbol length in the time domain and one subcarrier in the frequency domain (represented as a block of the resource grid) is referred to as a resource element (RE). As such, in the example of <FIG>, there are <NUM> resource elements in a resource block <NUM>.

LTE, and in some cases NR, utilize OFDM on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. Unlike LTE, however, NR has an option to use OFDM on the uplink as well. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers <NUM>, which are also commonly referred to as tones, bins, etc. Each subcarrier <NUM> may be modulated with data. The spacing between adjacent subcarriers <NUM> may be fixed, and the total number of subcarriers <NUM> (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers <NUM> may be <NUM> and the minimum resource allocation (resource block) may be <NUM> subcarriers <NUM> (or <NUM>). Consequently, the nominal FFT size may be equal to <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> megahertz (MHz), respectively. For example, a subband may cover <NUM> (i.e., <NUM> resource blocks), and there may be <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> subbands for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, respectively.

LTE supports a single numerology (subcarrier spacing, symbol length, etc.). In contrast NR may support multiple numerologies, for example, subcarrier spacing of <NUM>, <NUM>, <NUM>, <NUM> and <NUM> or greater may be available. Table <NUM> provided below lists some various parameters for different NR numerologies.

With continued reference to <FIG>, some of the resource elements, indicated as R<NUM> and R<NUM>, include a downlink reference signal (DL-RS). The DL-RS may include cell-specific RS (CRS) (also sometimes called common RS) and UE-specific RS (UE-RS). UE-RS are transmitted only on the resource blocks <NUM> upon which the corresponding physical downlink shared channel (PDSCH) is mapped. The number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks <NUM> that a UE receives and the higher the modulation scheme, the higher the data rate for the UE.

In an aspect, the DL-RS may be positioning reference signals (PRS). A base station may transmit radio frames (e.g., radio frames <NUM>), or other physical layer signaling sequences, supporting PRS signals according to frame configurations either similar to, or the same as that, shown in <FIG>, which may be measured and used for a UE (e.g., any of the UEs described herein) position estimation. Other types of wireless nodes (e.g., a distributed antenna system (DAS), remote radio head (RRH), UE, AP, etc.) in a wireless communications network may also be configured to transmit PRS signals configured in a manner similar to (or the same as) that depicted in <FIG>.

A collection of resource elements that are used for transmission of PRS is referred to as a "PRS resource. " The collection of resource elements can span multiple PRBs in the frequency domain and N (e.g., <NUM> or more) consecutive symbol(s) <NUM> within a slot <NUM> in the time domain. In a given OFDM symbol <NUM>, a PRS resource occupies consecutive PRBs. A PRS resource is described by at least the following parameters: PRS resource identifier (ID), sequence ID, comb size-N, resource element offset in the frequency domain, starting slot and starting symbol, number of symbols per PRS resource (i.e., the duration of the PRS resource), and QCL information (e.g., QCL with other DL reference signals). Currently, one antenna port is supported. The comb size indicates the number of subcarriers in each symbol carrying PRS. For example, a comb-size of comb-<NUM> means that every fourth subcarrier of a given symbol carries PRS.

A "PRS resource set" is a set of PRS resources used for the transmission of PRS signals, where each PRS resource has a PRS resource ID. In addition, the PRS resources in a PRS resource set are associated with the same transmission-reception point (TRP). A PRS resource ID in a PRS resource set is associated with a single beam transmitted from a single TRP (where a TRP may transmit one or more beams). That is, each PRS resource of a PRS resource set may be transmitted on a different beam, and as such, a "PRS resource" can also be referred to as a "beam. " Note that this does not have any implications on whether the TRPs and the beams on which PRS are transmitted are known to the UE. A "PRS occasion" is one instance of a periodically repeated time window (e.g., a group of one or more consecutive slots) where PRS are expected to be transmitted. A PRS occasion may also be referred to as a "PRS positioning occasion," a "positioning occasion," or simply an "occasion.

Note that the terms "positioning reference signal" and "PRS" may sometimes refer to specific reference signals that are used for positioning in LTE systems. However, as used herein, unless otherwise indicated, the terms "positioning reference signal" and "PRS" refer to any type of reference signal that can be used for positioning, such as but not limited to, PRS signals in LTE or <NUM>, transmitter reference signals (TRS), cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), primary synchronization signals (PSS), secondary synchronization signals (SSS), SSB, etc..

<FIG> illustrates exemplary DL PRSs <NUM> being processed through a wireless communications system according to aspects of the disclosure. In <FIG>, a PRS transmit beams are transmitted by a cell (or transmission reception point (TRP)) over a series of beam-specific positioning occasions on respective slots/symbols during a positioning session (TPRS). These PRS transmit beams are received as PRS receive beams at a UE, and then processed (e.g., various positioning measurements are made by the UE, etc.).

<FIG> illustrates an exemplary wireless communications system <NUM> according to aspects of the disclosure. In <FIG>, eNBi, eNB<NUM> and eNBs are synchronized with each other, such that TOA (e.g., TDOA) measurements (denoted as T<NUM>, T<NUM> and T<NUM>) can be used to generate a positioning estimate for a UE. Multiple TDOA measurements may be used for triangulation (e.g., <NUM> or more cells or eNBs). In TDOA-based positioning schemes, network synchronization error is the main bottleneck in terms of positioning accuracy.

Another positioning technique that requires cell (or satellite) synchronization is based on Observed Time Difference Of Arrival (OTDOA). One example OTDOA-based positioning scheme is GPS, which is limited to an accuracy of <NUM>-<NUM> ns (e.g., <NUM> - <NUM> meters).

In NR, there is no requirement for precise timing synchronization across the network. Instead, it is sufficient to have coarse time-synchronization across gNBs (e.g., within a cyclic prefix (CP) duration of the OFDM symbols). RTT-based methods generally only need coarse timing synchronization, and as such, are a preferred positioning method in NR.

In a network-centric RTT estimation, the serving base station (e.g., base station <NUM>) instructs the UE (e.g., UE <NUM>) to scan for / receive RTT measurement signals (e.g., PRS) on serving cells and two or more neighboring base stations (e.g., 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., location server <NUM>, LMF <NUM>). 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'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, UL-PRS) to the one or more base stations (e.g., when instructed by its serving base station) and may include the difference TRx→Tx (e.g., TRx→Tx <NUM> in <FIG>) 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 TTx→Rx (e.g., TTx→Rx <NUM> in <FIG>) between the transmission time of the RTT measurement signal and the ToA of the RTT response to the UE-reported difference TRx→Tx (e.g., TRx→Tx <NUM> in <FIG>), the base station can deduce the propagation time between the base station and the UE, from which it can then 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).

<FIG> illustrates an exemplary wireless communications system <NUM> according to aspects of the disclosure. In the example of <FIG>, a UE <NUM> (which may correspond to any of the UEs described herein) 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 <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM> (collectively, base stations <NUM>, and which may correspond to any of the base stations described herein) 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 three base stations <NUM>, as will be appreciated, there may be more UEs <NUM> and more base stations <NUM>.

To support position estimates, the base stations <NUM> may be configured to broadcast reference RF signals (e.g., PRS, NRS, CRS, TRS, CSI-RS, PSS, SSS, etc.) to UEs <NUM> in their coverage area to enable a UE <NUM> to measure characteristics of such reference RF signals. For example, the UE <NUM> may measure the ToA of specific reference RF signals (e.g., PRS, NRS, CRS, CSI-RS, etc.) transmitted by at least three different base stations <NUM> and may use the RTT positioning method to report these ToAs (and additional information) back to the serving base station <NUM> or another positioning entity (e.g., location server <NUM>, LMF <NUM>).

In an aspect, although described as the UE <NUM> measuring reference RF signals from a base station <NUM>, the UE <NUM> may measure reference RF signals from one of multiple cells supported by a base station <NUM>. Where the UE <NUM> measures reference RF signals transmitted by a cell supported by a base station <NUM>, the at least two other reference RF signals measured by the UE <NUM> to perform the RTT procedure would be from cells supported by base stations <NUM> different from the first base station <NUM> and may have good or poor signal strength at the UE <NUM>.

In order to determine the position (x, y) of the UE <NUM>, the entity determining the position of the UE <NUM> needs to know the locations of the base stations <NUM>, which may be represented in a reference coordinate system as (xk, yk), where k=<NUM>, <NUM>, <NUM> in the example of <FIG>. Where one of the base stations <NUM> (e.g., the serving base station) or the UE <NUM> determines the position of the UE <NUM>, the locations of the involved base stations <NUM> may be provided to the serving base station <NUM> or the UE <NUM> by a location server with knowledge of the network geometry (e.g., location server <NUM>, LMF <NUM>). Alternatively, the location server may determine the position of the UE <NUM> using the known network geometry.

Either the UE <NUM> or the respective base station <NUM> may determine the distance (dk, where k=<NUM>, <NUM>, <NUM>) between the UE <NUM> and the respective base station <NUM>. In an aspect, determining the RTT <NUM> of signals exchanged between the UE <NUM> and any base station <NUM> can be performed and converted to a distance (dk). As discussed further below, RTT techniques can measure the time between sending a signaling message (e.g., reference RF signals) and receiving a response. These methods may utilize calibration to remove any processing delays. In some environments, it may be assumed that the processing delays for the UE <NUM> and the base stations <NUM> are the same. However, such an assumption may not be true in practice.

Once each distance dk is determined, the UE <NUM>, a base station <NUM>, or the location server (e.g., location server <NUM>, LMF <NUM>) can solve for the position (x, y) of the UE <NUM> by using a variety of known geometric techniques, such as, for example, trilateration. From <FIG>, it can be seen that the position of the UE <NUM> ideally lies at the common intersection of three semicircles, each semicircle being defined by radius dk and center (xk, yk), where k=<NUM>, <NUM>, <NUM>.

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 <NUM> from the location of a base station <NUM>). The intersection of the two directions at or near the point (x, y) can provide another estimate of the location for the UE <NUM>.

A position estimate (e.g., for a UE <NUM>) 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).

<FIG> illustrates an exemplary wireless communications system <NUM> according to aspects of the disclosure. While <FIG> depicts an example of a multi-cell RTT positioning scheme, <FIG> depicts an example of a single-cell RTT positioning scheme. In <FIG>, RTT<NUM> is measured along with an AoDi associated with a beam on which a DL PRS is transmitted from a cell to a UE. The overlapping region of the RTT<NUM> and AoD<NUM> depicted in <FIG> provides a coarse location estimate for the associated UE.

<FIG> is a diagram <NUM> showing exemplary timings of RTT measurement signals exchanged between a base station <NUM> (e.g., any of the base stations described herein) and a UE <NUM> (e.g., any of the UEs described herein), according to aspects of the disclosure. In the example of <FIG>, the base station <NUM> sends an RTT measurement signal <NUM> (e.g., PRS, NRS, CRS, CSI-RS, etc.) to the UE <NUM> at time T<NUM>. The RTT measurement signal <NUM> has some propagation delay TProp as it travels from the base station <NUM> to the UE <NUM>. At time T<NUM> (the ToA of the RTT measurement signal <NUM> at the UE <NUM>), the UE <NUM> receives/measures the RTT measurement signal <NUM>. After some UE processing time, the UE <NUM> transmits an RTT response signal <NUM> at time T<NUM>. After the propagation delay TProp, the base station <NUM> receives/measures the RTT response signal <NUM> from the UE <NUM> at time T<NUM> (the ToA of the RTT response signal <NUM> at the base station <NUM>).

In order to identify the ToA (e.g., T<NUM>) of a reference signal (e.g., an RTT measurement signal <NUM>) transmitted by a given network node (e.g., base station <NUM>), the receiver (e.g., UE <NUM>) first jointly processes all the resource elements (REs) on the channel on which the transmitter is transmitting the reference signal, and performs an inverse Fourier transform to convert the received reference signals to the time domain. The conversion of the received reference signals to the time domain is referred to as estimation of the channel energy response (CER). The CER shows the peaks on the channel over time, and the earliest "significant" peak should therefore correspond to the ToA of the reference signal. Generally, the receiver will use a noise-related quality threshold to filter out spurious local peaks, thereby presumably correctly identifying significant peaks on the channel. For example, the receiver may chose a ToA estimate that is the earliest local maximum of the CER that is at least X dB higher than the median of the CER and a maximum Y dB lower than the main peak on the channel. The receiver determines the CER for each reference signal from each transmitter in order to determine the ToA of each reference signal from the different transmitters.

In some designs, the RTT response signal <NUM> may explicitly include the difference between time T<NUM> and time T<NUM> (i.e., TRx→Tx <NUM>). Using this measurement and the difference between time T<NUM> and time T<NUM> (i.e., TTx→Rx <NUM>), the base station <NUM> (or other positioning entity, such as location server <NUM>, LMF <NUM>) can calculate the distance to the UE <NUM> as: <MAT> where c is the speed of light.

<FIG> illustrates is a diagram <NUM> showing exemplary timings of RTT measurement signals exchanged between a base station (e.g., any of the base stations described herein) and a UE (e.g., any of the UEs described herein), according to other aspects of the disclosure. In particular, <NUM>-<NUM> of <FIG> denote portions of frame delay that are associated with a Rx-Tx differences as measured at the gNB and UE, respectively.

An additional source of delay or error is due to UE and gNB hardware group delay for position location. <FIG> illustrates a diagram <NUM> showing exemplary timings of RTT measurement signals exchanged between a base station (gNB) (e.g., any of the base stations described herein) and a UE (e.g., any of the UEs described herein), according to aspects of the disclosure. <FIG> is similar in some respects to <FIG>. However, in <FIG>, the UE and gNB hardware group delay (which is primarily due to internal hardware delays between a baseband (BB) component and antenna at the UE and gNB) is shown with respect <NUM>-<NUM> (denoted as ΔRx and ΔTx). As will be appreciated, both Tx-side and Rx-side path-specific or beam-specific delays impact the RTT measurement.

<FIG> illustrates an exemplary wireless communications system <NUM> according to aspects of the disclosure. The wireless communications system <NUM> is similar to the wireless communications system <NUM> of <FIG>. However, the wireless communications system <NUM> further depicts the beams associated with the respective TOA (e.g., TDOA) measurements (denoted as T<NUM>, T<NUM> and T<NUM>). As will be appreciated, Rx-side path-specific or beam-specific delays impact the DL TDOA measurement. While not shown explicitly, Tx-side path-specific or beam-specific delays impact UL TDOA measurements in a similar manner.

The precision of positioning estimates at the UE is on UE-side is limited by how finely group-delay / timing errors can be maintained. For example, <NUM> ns error for ΔRx and ΔTx can lead to an approximate <NUM> foot limit on precision. Some 3GPP standards are targeting as a positioning precision of less than <NUM> (for Rel-<NUM>) and less than <NUM> (for general commercial for Rel-<NUM>). Knowledge of UE and/or gNB hardware group delay may thereby help to improve location accuracy.

As an example, in RTT-based positioning, RTT can be estimated between a UE and two gNBs. The positioning estimate for the UE can then be narrowed to the intersection of a geographic range that maps to these two RTTs (e.g., to a hyperbola). RTTs to additional gNBs (or to particular TRPs of such gNBs) can further narrow (or refine) the positioning estimate for the UE. Differential RTT is a positioning scheme whereby a difference between two RTT measurements (or measurement ranges) is used to generate a positioning estimate for a UE.

In some designs, a positioning engine (e.g., at the UE, base station, or server/LMF) can select between whether RTT measurements are to be used to compute a positioning estimate using typical RTT or differential RTT. For example, if the positioning engine receives RTTs that are known to have already accounted for hardware group delays, then typical RTT positioning is performed (e.g., as shown in <FIG>). Otherwise, in some designs, differential RTT is performed so that some of the hardware group delay can be canceled out. In some designs where the positioning engine is implemented at the network-side (e.g., gNB/LMU/eSMLC/LMF), the group hardware delay at the UE is not known (and vice versa).

An example of theoretical Rx-Tx delay measurements between a UE and base stations <NUM> and <NUM>, respectively, is as follows: <MAT> <MAT> whereby w denotes the hardware group delay.

As will be appreciated, if the hardware group delay w is the same for both <MAT> and <MAT>, then the hardware group delay w cancels out completely when a differential is taken between <MAT> and <MAT>. One problem that may occur is that the hardware group delay w does not actually remain constant, but rather changes over time, as follows: <MAT> <MAT> whereby w(t<NUM>) and w(t<NUM>) reflect the at times ti and t<NUM>, respectively.

In this case, a residual error is present due to the differential between w(t<NUM>) and w(t<NUM>) when a differential is taken between <MAT> and <MAT>. This residual error is due to a phenomenon referred to herein as time drift. As an example, time drift in a hardware group delay can occur due to various environmental factors, such as humidity, temperature, and so on.

Another problem with differential RTT may occur where the UE-side hardware group delay (e.g., <NUM> in <FIG>, <NUM>-<NUM> in <FIG>) is effectively canceled out along with a reference gNB hardware group delay, but a residual gNB hardware group delay persists. For example, a residual gNB hardware group delay for gNB i may be denoted as GD,diff,gNB,i, e.g.: <MAT> whereby GDgNB,i is the hardware group delay for gNB i (e.g., <NUM> or <NUM> of <FIG>) and GDgNB_ref is the hardware group delay for the reference gNB. GDgNB_ref is common across all RTTs associated with the differential RTT positioning procedure.

While described above with respect to a reference gNB, in other designs, any wireless communications device associated with a known location (e.g., a reference UE with a recent positioning fix, etc.) may be used as a reference device in various positioning schemes (e.g., RTT, differential RTT, double differential RTT, TDOA, etc.). In some systems, the reference device (e.g., gNB or reference UE) is selected based on signal quality criteria such as RSRP. However, a reference device (e.g., gNB or reference UE) with good signal quality is not necessarily the best choice in terms of hardware group delay calibration. Aspects of the disclosure are thereby directed to reference device (e.g., gNB or reference UE) selection based at least in part upon hardware group delay calibration capabilities associated with the reference devices (e.g., gNBs and/or reference UEs) associated with a positioning procedure (e.g., RTT, differential RTT, double differential RTT, TDOA, etc.) for a UE. Such aspects may provide various technical advantages, including improved positioning estimate precision for UEs.

<FIG> illustrates an exemplary process <NUM> of wireless communication, according to aspects of the disclosure. The process <NUM> may be performed by a communications node. In some designs, the communications node that performs the process <NUM> is a UE (e.g., any of the UEs described herein, such as UE <NUM>). In other designs, the communications node that performs the process <NUM> is a BS (e.g., any of the BSs or gNBs described herein, such as BS <NUM>, which may comprise an integrated LMF). In other designs, the communications node that performs the process <NUM> is a network entity, such as network entity <NUM> (e.g., LMF). Moreover, while the process <NUM> is described in some aspects with respect to RTT (e.g., differential RTT), in some designs the process <NUM> of <FIG> may also be applicable to other types of RTT (e.g., double differential RTT, where a first differential RTT is measured between a target UE and two reference nodes and a second differential RTT is measured between a reference device and the two reference nodes) or non-RTT positioning techniques such as DL or UL TDOA.

At <NUM>, the communications node (e.g., receiver <NUM>, receiver <NUM>, receiver <NUM>, receiver <NUM>, processing system <NUM>, memory component <NUM>, etc.) obtains a hardware group delay calibration capability associated with each of a plurality of reference devices (e.g., gNBs and/or reference UEs) associated with a positioning procedure for a UE. In an example, the communications node may correspond to the UE, and the positioning procedure (e.g., traditional RTT, differential RTT, double differential RTT, TDOA, etc.) is a UE-based positioning procedure. In another example, the communications node may correspond to a network device (e.g., gNB, LMF, etc.), and the positioning procedure (e.g., traditional RTT, differential RTT, double differential RTT, TDOA, etc.) is a network-based positioning procedure.

At <NUM>, the communications node (e.g., processing system <NUM>, processing system <NUM>, processing system <NUM>, etc.) selects a reference device (e.g., gNB or reference UE) from among the plurality of reference devices based at least on the hardware group delay calibration capabilities associated with the plurality of reference devices. For example, assume that each reference device (e.g., gNB or reference UE) reports its hardware group delay calibration capability as a respective hardware group delay error range of [-T1, +T1] ns. In some designs, the communications node at <NUM> may select, as the selected reference device (e.g., gNB or reference UE), the reference device (e.g., gNB or reference UE) for the positioning procedure (e.g., traditional RTT, differential RTT, double differential RTT, TDOA, etc.) as the reference device associated with the narrowest hardware group delay error range (e.g., or smallest value of T1). In some designs, the selection of <NUM> may select the reference device based on the hardware group delay calibration capabilities associated with the plurality of reference devices and at least one secondary criteria. For example, the at least one secondary criteria may comprise RSRP measurements between the plurality of reference devices and the UE (e.g., a higher RSRP measurement may weight a respective reference device more favorably in terms of reference device selection).

At <NUM>, the communications node (e.g., processing system <NUM>, processing system <NUM>, processing system <NUM>, components <NUM>/<NUM>/<NUM>, etc.) determines (e.g., calibrates) one or more timing (e.g., positioning) measurements associated with each of the plurality of reference devices based on a reference hardware group delay calibration value (GDgNB_ref) associated with the selected reference device (e.g., as in Equation <NUM>, above).

Referring to <FIG>, in some designs, the communications node may transmit a hardware group delay calibration capability request to each of the plurality of reference devices, wherein the obtaining comprises receiving the hardware group delay calibration capability for each of the plurality of reference devices in response to the request. In an example, for UE-based positioning, the UE may transmit the requests to the reference devices (e.g., BSs and/or reference UEs), which then report their hardware group delay calibration capabilities to the LMF, which in turn propagates this information back to the UE. In other designs, for network-based positioning, the LMF may transmit the requests to the reference devices (e.g., BSs and/or reference UEs), which then report their hardware group delay calibration capabilities to the LMF.

Referring to <FIG>, in some designs, the hardware group delay calibration capability for at least one of the plurality of reference devices (e.g., BSs and/or reference UEs) is specific to a particular set of frequency-domain resources, a particular set of beams, a particular transmission reception point (TRP). For example, in some designs, each reference device (e.g., gNB or UE) may report its respective hardware group delay calibration capability (or calibration error) with an indication of an associated timestamp, band, positioning frequency layer, UE ID, and/or TRP ID. In some designs, the hardware group delay calibration capability (or calibration error) may be different for different bands. In some designs, certain parameters may be grouped or common with respect to a positioning frequency layer (e.g., the center frequency), in which case the hardware group delay calibration capability (or calibration error) may be specific to a positioning frequency layer. In some designs, different beams may be associated with a different hardware group delay calibration capability (or calibration error), e.g., UE/TRP may have multiple antenna panels, in which case the hardware group delay calibration capability (or calibration error) may be specific to a particular UE ID or TRP.

Referring to <FIG>, in some designs, the hardware group delay calibration capability for at least one of the plurality of reference devices (e.g., BSs and/or reference UEs) is time-varying. In this case, at block <NUM>, the communications node may obtain at least one parameter (e.g., a timestamp, etc.) for modeling a time-varying function of the hardware group delay calibration capability of the at least one reference device (e.g., BS or reference UE).

Referring to <FIG>, in some designs, at block <NUM>, the communications node may receive differential hardware group delay calibration capability information that is relative to previously received hardware group delay calibration capability information. For example, if the hardware group delay calibration capability of particular reference devices (e.g., BSs and/or reference UEs) changes infrequently, then differential reporting can be used to reduce report overhead.

As noted above with respect to Equation <NUM>, in a gNB-specific example, the residual gNB hardware group delay (GD,diff,gNB,i) is a factor that can reduce precision of UE positioning. Aspects of the disclosure are thereby directed to estimation of the residual reference device (e.g., gNB or reference UE) hardware group delay (e.g., in a gNB-specific example, GD,diff,gNB,i) so that the residual reference device hardware group delay (e.g., in a gNB-specific example, GD,diff,gNB,i) can be canceled out during a position estimation procedure for a UE. Such aspects may provide various technical advantages, including improved positioning estimate precision for UEs.

<FIG> illustrates an exemplary process <NUM> of wireless communication, according to aspects of the disclosure. The process <NUM> may be performed by a communications node. In some designs, the communications node that performs the process <NUM> a BS (e.g., any of the BSs or gNBs described herein, such as BS <NUM>, which may comprise an integrated LMF). In other designs, the communications node that performs the process <NUM> is a network entity, such as network entity <NUM> (e.g., LMF). Moreover, while the process <NUM> is described in some aspects with respect to RTT (e.g., differential RTT), in some designs the process <NUM> of <FIG> may also be applicable to other types of RTT (e.g., double differential RTT, where a first differential RTT is measured between a target UE and two reference nodes and a second differential RTT is measured between a reference device and the two reference nodes) or non-RTT positioning techniques such as DL or UL TDOA.

At <NUM>, the communications node (e.g., receiver <NUM>, receiver <NUM>, positioning component <NUM> or <NUM>, receiver <NUM>, etc.) obtains an estimated distance between a first reference device (e.g., gNB or reference UE) and a second reference device (e.g., gNB or reference UE) that is based on one or more timing measurements of one or more reference signals for positioning between the first and second reference devices. In some designs, one or more timing measurements may be associated with an RTT measurement (e.g., traditional RTT, differential RTT, double differential RTT, etc.), similar to <FIG> or <FIG> except that the reference signals for positioning are exchanged between two reference devices (e.g., BSs or gNBs or reference UEs) instead of between a UE and a BS. In other designs, the one or more timing measurements may be associated with a UL or DL TDOA measurement. In some designs, the one or more reference signals may be configured similarly to PRSs, although this is optional. In some designs, the one or more reference signals for positioning may correspond to OTA signals with a direct LOS between the first and second reference devices (e.g., gNBs and/or reference UEs).

At <NUM>, the communications node (e.g., processing system <NUM> or <NUM>, positioning component <NUM> or <NUM>, etc.) estimates a hardware group delay associated with the first and second reference devices based on (i) the estimated distance between the first and second reference devices, and (ii) a known distance between the first and second reference devices. In an example, the known distance between the first and second reference devices may be preconfigured or predetermined based on known locations for the first and second reference devices (e.g., obtained from a base station almanac or recent positioning fixes of reference UEs, etc.).

Referring to <FIG>, in some designs, the communications node corresponds to one of the first and second reference devices (e.g., base stations or reference UEs). In other designs, wherein the communications node corresponds to a network entity (e.g., LMF) separate from the first and second reference devices.

Referring to <FIG>, in a gNB-specific example, the first reference device may correspond to a reference base station (gNB_ref), and the estimated hardware group delay at <NUM> may correspond to a residual gNB hardware group delay (GD,diff,gNB,i) between reference base station (gNB_ref) and the second base station (gNB_i), e.g.: <MAT> whereby RTTi is the estimated distance between the first and second base stations (e.g., gNB_ref and gNB_i), GD,diff,gNB,i is the overall group delay error between gNB_ref and gNB_i, and Distance_i is the known distance between the first and second base stations (e.g., obtained based on base station almanac).

In an example, an RTT measurement between the first reference device (reference gNB) and the second reference device (gNB_i) may be implemented as follows:.

As noted above, the reference device(s) may alternatively correspond to reference UE(s), instead of gNBs. Moreover, while an RTT-specific example is provided above, in other designs the positioning procedure may be non-RTT, such as TDOA.

In some designs, the process <NUM> of <FIG> may be implemented between a designated reference device (e.g., gNB or reference UE) and a plurality of other reference devices (e.g., each other gNB or reference UE associated with a positioning procedure, such as differential RTT positioning procedure, for a particular UE). In other designs, the process <NUM> of <FIG> may be performed only for reference devices that have a direct LOS connection to the designated reference device. In other designs, the process <NUM> of <FIG> may be performed on a periodic basis rather than being event-triggered based on a positioning procedure.

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 DSP, an ASIC, an 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.

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 random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The ASIC may reside in a user terminal (e.g., UE).

In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. 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. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

Claim 1:
A method of operating a communications node, comprising:
transmitting a hardware group delay calibration capability request to each of a plurality of reference devices (<NUM>), the plurality of reference devices (<NUM>) comprising at least one base station (<NUM>), at least one reference user equipment (<NUM>), UE, or a combination thereof,
obtaining a hardware group delay calibration capability associated with each of the plurality of reference devices (<NUM>), wherein the obtaining comprises receiving the hardware group delay calibration capability for each of the plurality of reference devices (<NUM>) in response to the request, the hardware group delay calibration capability indicating a respective hardware group delay error range;
selecting a reference device (<NUM>) from among the plurality of reference devices (<NUM>) based at least on the hardware group delay calibration capabilities associated with the plurality of reference devices (<NUM>); and
determining one or more timing measurements (<NUM>) associated with each of the plurality of reference devices (<NUM>) based on a reference hardware group delay calibration value associated with the selected reference device (<NUM>).