Patent Publication Number: US-2022240322-A1

Title: Calibration of angular measurement bias for positioning of a user equipment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present Application for Patent claims the benefit of U.S. Provisional Application No. 63/138,490, entitled “CALIBRATION OF ANGULAR MEASUREMENT BIAS FOR POSITIONING OF A USER EQUIPMENT,” filed Jan. 17, 2021, assigned to the assignee hereof, and expressly incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     Aspects of the disclosure relate generally to wireless communications, and more particularly to calibration of angular measurement bias for positioning of a user equipment (UE). 
     2. Description of the Related Art 
     Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G networks), a third-generation (3G) high speed data, Internet-capable wireless service and a fourth-generation (4G) 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 (5G) wireless standard, referred to as New Radio (NR), enables higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with 1 gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large wireless sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards. 
     SUMMARY 
     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 device includes obtaining a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtaining a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and calibrating the second AoA measurement based on the residual AoA bias. 
     In an aspect, a method of operating a communications device includes obtaining a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtaining a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and calibrating the second AoD measurement based on the residual AoD bias. 
     In an aspect, a communications device 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 residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtain a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and calibrate the second AoA measurement based on the residual AoA bias. 
     In an aspect, a communications device 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 residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtain a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and calibrate the second AoD measurement based on the residual AoD bias. 
     In an aspect, a communications device includes means for obtaining a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; means for obtaining a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and means for calibrating the second AoA measurement based on the residual AoA bias. 
     In an aspect, a communications device includes means for obtaining a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; means for obtaining a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and means for calibrating the second AoD measurement based on the residual AoD bias. 
     In an aspect, a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a communications device, cause the communications device to: obtain a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtain a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and calibrate the second AoA measurement based on the residual AoA bias. 
     In an aspect, a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a communications device, cause the communications device to: obtain a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtain a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and calibrate the second AoD measurement based on the residual AoD bias. 
     Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are presented to aid in the description of various aspects of the disclosure and are provided solely for illustration of the aspects and not limitation thereof. 
         FIG. 1  illustrates an exemplary wireless communications system, according to various aspects. 
         FIGS. 2A and 2B  illustrate example wireless network structures, according to various aspects. 
         FIGS. 3A to 3C  are simplified block diagrams of several sample aspects of components that may be employed in wireless communication nodes and configured to support communication as taught herein. 
         FIGS. 4A and 4B  are diagrams illustrating examples of frame structures and channels within the frame structures, according to aspects of the disclosure. 
         FIG. 5  illustrates an exemplary PRS configuration for a cell supported by a wireless node. 
         FIG. 6  illustrates an exemplary wireless communications system according to various aspects of the disclosure. 
         FIG. 7  illustrates an exemplary wireless communications system according to various aspects of the disclosure. 
         FIG. 8A  is a graph showing the RF channel response at a receiver over time according to aspects of the disclosure. 
         FIG. 8B  is a diagram illustrating this separation of clusters in AoD. 
         FIG. 9  is a diagram showing exemplary timings of RTT measurement signals exchanged between a base station and a UE, according to aspects of the disclosure. 
         FIG. 10  is a diagram showing exemplary timings of RTT measurement signals exchanged between a base station and a UE, according to other aspects of the disclosure. 
         FIG. 11  illustrates an exemplary wireless communications system according to aspects of the disclosure. 
         FIG. 12  illustrates is a diagram 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. 
         FIG. 13  illustrates an exemplary process of wireless communication, according to aspects of the disclosure. 
         FIG. 14  illustrates a gNB configuration in accordance with an aspect of the disclosure. 
         FIG. 15  illustrates an example implementation of the process of  FIG. 13  in accordance with an aspect of the disclosure. 
         FIG. 16  illustrates an example implementation of the process of  FIG. 13  in accordance with an aspect of the disclosure. 
         FIG. 17  illustrates an example implementation of the process of  FIG. 13  in accordance with an aspect of the disclosure. 
         FIG. 18  illustrates an exemplary process of wireless communication, according to aspects of the disclosure. 
         FIG. 19  illustrates an example implementation of the process of  FIG. 18  in accordance with an aspect of the disclosure. 
         FIG. 20  illustrates an example implementation of the process of  FIG. 18  in accordance with an aspect of the disclosure. 
         FIG. 21  illustrates an example implementation of the process of  FIG. 18  in accordance with an aspect of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the disclosure are provided in the following description and related drawings directed to various examples provided for illustration purposes. Alternate aspects may be devised without departing from the scope of the disclosure. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure. 
     The words “exemplary” and/or “example” are used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” and/or “example” is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term “aspects of the disclosure” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. 
     Those of skill in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description below may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, in part on the desired design, in part on the corresponding technology, etc. 
     Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. Additionally, the sequence(s) of actions described herein can be considered to be embodied entirely within any form of non-transitory computer-readable storage medium having stored therein a corresponding set of computer instructions that, upon execution, would cause or instruct an associated processor of a device to perform the functionality described herein. Thus, the various aspects of the disclosure 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” perform the described action. 
     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, consumer or consumer asset 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 802.11, etc.) and so on. 
     A base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed, and may be alternatively referred to as an access point (AP), a network node, a NodeB, an evolved NodeB (eNB), a 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. In some systems, a base station may correspond to a Customer Premise Equipment (CPE) or a road-side unit (RSU). In some designs, a base station may correspond to a high-powered UE (e.g., a vehicle UE or VUE) that may provide limited certain infrastructure functionality. 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-reception point (TRP) or to multiple physical TRPs that may or may not be co-located. For example, where the term “base station” refers to a single physical TRP, the physical TRP 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 TRPs, the physical TRPs 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 TRPs, the physical TRPs 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 TRPs 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. Because a TRP is the point from which a base station transmits and receives wireless signals, as used herein, references to transmission from or reception at a base station are to be understood as referring to a particular TRP of the base station. 
     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. 1  illustrates an exemplary wireless communications system  100 . The wireless communications system  100  (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations  102  and various UEs  104 . The base stations  102  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  100  corresponds to an LTE network, or gNBs where the wireless communications system  100  corresponds to a NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc. 
     The base stations  102  may collectively form a RAN and interface with a core network  170  (e.g., an evolved packet core (EPC) or next generation core (NGC)) through backhaul links  122 , and through the core network  170  to one or more location servers  172 . In addition to other functions, the base stations  102  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  102  may communicate with each other directly or indirectly (e.g., through the EPC/NGC) over backhaul links  134 , which may be wired or wireless. 
     The base stations  102  may wirelessly communicate with the UEs  104 . Each of the base stations  102  may provide communication coverage for a respective geographic coverage area  110 . In an aspect, one or more cells may be supported by a base station  102  in each coverage area  110 . 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 (PCI), a virtual cell identifier (VCI)) 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. Because a cell is supported by a specific base station, the term “cell” may refer to either or both the logical communication entity and the base station that supports it, depending on the context. 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  110 . 
     While neighboring macro cell base station  102  geographic coverage areas  110  may partially overlap (e.g., in a handover region), some of the geographic coverage areas  110  may be substantially overlapped by a larger geographic coverage area  110 . For example, a small cell base station  102 ′ may have a coverage area  110 ′ that substantially overlaps with the coverage area  110  of one or more macro cell base stations  102 . 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  120  between the base stations  102  and the UEs  104  may include UL (also referred to as reverse link) transmissions from a UE  104  to a base station  102  and/or downlink (DL) (also referred to as forward link) transmissions from a base station  102  to a UE  104 . The communication links  120  may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links  120  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). 
     The wireless communications system  100  may further include a wireless local area network (WLAN) access point (AP)  150  in communication with WLAN stations (STAs)  152  via communication links  154  in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in an unlicensed frequency spectrum, the WLAN STAs  152  and/or the WLAN AP  150  may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure prior to communicating in order to determine whether the channel is available. 
     The small cell base station  102 ′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station  102 ′ may employ LTE or NR technology and use the same 5 GHz unlicensed frequency spectrum as used by the WLAN AP  150 . The small cell base station  102 ′, employing LTE/5G in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. NR in unlicensed spectrum may be referred to as NR-U. LTE in an unlicensed spectrum may be referred to as LTE-U, licensed assisted access (LAA), or MulteFire. 
     The wireless communications system  100  may further include a millimeter wave (mmW) base station  180  that may operate in mmW frequencies and/or near mmW frequencies in communication with a UE  182 . Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band have high path loss and a relatively short range. The mmW base station  180  and the UE  182  may utilize beamforming (transmit and/or receive) over a mmW communication link  184  to compensate for the extremely high path loss and short range. Further, it will be appreciated that in alternative configurations, one or more base stations  102  may also transmit using mmW or near mmW and beamforming. Accordingly, it will be appreciated that the foregoing illustrations are merely examples and should not be construed to limit the various aspects disclosed herein. 
     Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omni-directionally). With transmit beamforming, the network node determines where a given target device (e.g., a UE) is located (relative to the transmitting network node) 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 receiving device(s). To change the directionality of the RF signal when transmitting, a network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters that are broadcasting the RF signal. For example, a network node may use an array of antennas (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 from the transmitter 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 to suppress radiation in undesired directions. 
     Transmit beams may be quasi-collocated, meaning that they appear to the receiver (e.g., a UE) as having the same parameters, regardless of whether or not the transmitting antennas of the network node themselves are physically collocated. In NR, there are four types of quasi-collocation (QCL) relations. Specifically, a QCL relation of a given type means that certain parameters about a second reference RF signal on a second beam can be derived from information about a source reference RF signal on a source beam. Thus, if the source reference RF signal is QCL Type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type D, the receiver can use the source reference RF signal to estimate the spatial receive parameter of a second reference RF signal transmitted on the same channel. 
     In receive beamforming, the receiver uses a receive beam to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting and/or adjust the phase setting of an array of antennas in a particular direction to amplify (e.g., to increase the gain level of) the RF signals received from that direction. Thus, when a receiver is said to beamform in a certain direction, it means the beam gain in that direction is high relative to the beam gain along other directions, or the beam gain in that direction is the highest compared to the beam gain in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) of the RF signals received from that direction. 
     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. 
     Note that a “downlink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. If the UE is forming the downlink beam, however, it is a receive beam to receive the downlink reference signal. Similarly, an “uplink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the uplink beam, it is an uplink receive beam, and if a UE is forming the uplink beam, it is an uplink transmit beam. 
     In 5G, the frequency spectrum in which wireless nodes (e.g., base stations  102 / 180 , UEs  104 / 182 ) operate is divided into multiple frequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In a multi-carrier system, such as 5G, 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  104 / 182  and the cell in which the UE  104 / 182  either performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels, and may be a carrier in a licensed frequency (however, this is not always the case). 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  104  and the anchor carrier and that may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier in an unlicensed frequency. 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  104 / 182  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  104 / 182  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. 
     For example, still referring to  FIG. 1 , one of the frequencies utilized by the macro cell base stations  102  may be an anchor carrier (or “PCell”) and other frequencies utilized by the macro cell base stations  102  and/or the mmW base station  180  may be secondary carriers (“SCells”). The simultaneous transmission and/or reception of multiple carriers enables the UE  104 / 182  to significantly increase its data transmission and/or reception rates. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz), compared to that attained by a single 20 MHz carrier. 
     The wireless communications system  100  may further include one or more UEs, such as UE  190 , 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. 1 , UE  190  has a D2D P2P link  192  with one of the UEs  104  connected to one of the base stations  102  (e.g., through which UE  190  may indirectly obtain cellular connectivity) and a D2D P2P link  194  with WLAN STA  152  connected to the WLAN AP  150  (through which UE  190  may indirectly obtain WLAN-based Internet connectivity). In an example, the D2D P2P links  192  and  194  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  100  may further include a UE  164  that may communicate with a macro cell base station  102  over a communication link  120  and/or the mmW base station  180  over a mmW communication link  184 . For example, the macro cell base station  102  may support a PCell and one or more SCells for the UE  164  and the mmW base station  180  may support one or more SCells for the UE  164 . 
     According to various aspects,  FIG. 2A  illustrates an example wireless network structure  200 . For example, an NGC  210  (also referred to as a “5GC”) can be viewed functionally as control plane functions  214  (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane functions  212 , (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)  213  and control plane interface (NG-C)  215  connect the gNB  222  to the NGC  210  and specifically to the control plane functions  214  and user plane functions  212 . In an additional configuration, an eNB  224  may also be connected to the NGC  210  via NG-C  215  to the control plane functions  214  and NG-U  213  to user plane functions  212 . Further, eNB  224  may directly communicate with gNB  222  via a backhaul connection  223 . In some configurations, the New RAN  220  may only have one or more gNBs  222 , while other configurations include one or more of both eNBs  224  and gNBs  222 . Either gNB  222  or eNB  224  may communicate with UEs  204  (e.g., any of the UEs depicted in  FIG. 1 ). Another optional aspect may include location server  230 , which may be in communication with the NGC  210  to provide location assistance for UEs  204 . The location server  230  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  230  can be configured to support one or more location services for UEs  204  that can connect to the location server  230  via the core network, NGC  210 , and/or via the Internet (not illustrated). Further, the location server  230  may be integrated into a component of the core network, or alternatively may be external to the core network. 
     According to various aspects,  FIG. 2B  illustrates another example wireless network structure  250 . For example, an NGC  260  (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)  264 , and user plane functions, provided by a session management function (SMF)  262 , which operate cooperatively to form the core network (i.e., NGC  260 ). User plane interface  263  and control plane interface  265  connect the eNB  224  to the NGC  260  and specifically to SMF  262  and AMF/UPF  264 , respectively. In an additional configuration, a gNB  222  may also be connected to the NGC  260  via control plane interface  265  to AMF/UPF  264  and user plane interface  263  to SMF  262 . Further, eNB  224  may directly communicate with gNB  222  via the backhaul connection  223 , with or without gNB direct connectivity to the NGC  260 . In some configurations, the New RAN  220  may only have one or more gNBs  222 , while other configurations include one or more of both eNBs  224  and gNBs  222 . Either gNB  222  or eNB  224  may communicate with UEs  204  (e.g., any of the UEs depicted in  FIG. 1 ). The base stations of the New RAN  220  communicate with the AMF-side of the AMF/UPF  264  over the N2 interface and the UPF-side of the AMF/UPF  264  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  204  and the SMF  262 , transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE  204  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  204 , and receives the intermediate key that was established as a result of the UE  204  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  204  and the location management function (LMF)  270 , as well as between the New RAN  220  and the LMF  270 , evolved packet system (EPS) bearer identifier allocation for interworking with the EPS, and UE  204  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  262  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  262  communicates with the AMF-side of the AMF/UPF  264  is referred to as the N 11  interface. 
     Another optional aspect may include a LMF  270 , which may be in communication with the NGC  260  to provide location assistance for UEs  204 . The LMF  270  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  270  can be configured to support one or more location services for UEs  204  that can connect to the LMF  270  via the core network, NGC  260 , and/or via the Internet (not illustrated). 
       FIGS. 3A, 3B, and 3C  illustrate several sample components (represented by corresponding blocks) that may be incorporated into a UE  302  (which may correspond to any of the UEs described herein), a base station  304  (which may correspond to any of the base stations described herein), and a network entity  306  (which may correspond to or embody any of the network functions described herein, including the location server  230  and the LMF  270 ) 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  302  and the base station  304  each include wireless wide area network (WWAN) transceiver  310  and  350 , respectively, configured to communicate via one or more wireless communication networks (not shown), such as an NR network, an LTE network, a GSM network, and/or the like. The WWAN transceivers  310  and  350  may be connected to one or more antennas  316  and  356 , respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc., via at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communication medium of interest (e.g., some set of time/frequency resources in a particular frequency spectrum). The WWAN transceivers  310  and  350  may be variously configured for transmitting and encoding signals  318  and  358  (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals  318  and  358  (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the transceivers  310  and  350  include one or more transmitters  314  and  354 , respectively, for transmitting and encoding signals  318  and  358 , respectively, and one or more receivers  312  and  352 , respectively, for receiving and decoding signals  318  and  358 , respectively. 
     The UE  302  and the base station  304  also include, at least in some cases, wireless local area network (WLAN) transceivers  320  and  360 , respectively. The WLAN transceivers  320  and  360  may be connected to one or more antennas  326  and  366 , respectively, for communicating with other network nodes, such as other UEs, access points, base stations, etc., via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth®, etc.) over a wireless communication medium of interest. The WLAN transceivers  320  and  360  may be variously configured for transmitting and encoding signals  328  and  368  (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals  328  and  368  (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the transceivers  320  and  360  include one or more transmitters  324  and  364 , respectively, for transmitting and encoding signals  328  and  368 , respectively, and one or more receivers  322  and  362 , respectively, for receiving and decoding signals  328  and  368 , respectively. 
     Transceiver circuitry including 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) 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. In an aspect, a transmitter may include or be coupled to a plurality of antennas (e.g., antennas  316 ,  336 , and  376 ), such as an antenna array, that permits the respective apparatus to perform transmit “beamforming,” as described herein. Similarly, a receiver may include or be coupled to a plurality of antennas (e.g., antennas  316 ,  336 , and  376 ), such as an antenna array, that permits the respective apparatus to perform receive beamforming, as described herein. In an aspect, the transmitter and receiver may share the same plurality of antennas (e.g., antennas  316 ,  336 , and  376 ), such that the respective apparatus can only receive or transmit at a given time, not both at the same time. A wireless communication device (e.g., one or both of the transceivers  310  and  320  and/or  350  and  360 ) of the apparatuses  302  and/or  304  may also comprise a network listen module (NLM) or the like for performing various measurements. 
     The apparatuses  302  and  304  also include, at least in some cases, satellite positioning systems (SPS) receivers  330  and  370 . The SPS receivers  330  and  370  may be connected to one or more antennas  336  and  376 , respectively, for receiving SPS signals  338  and  378 , respectively, such as global positioning system (GPS) signals, global navigation satellite system (GLONASS) signals, Galileo signals, Beidou signals, Indian Regional Navigation Satellite System (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. The SPS receivers  330  and  370  may comprise any suitable hardware and/or software for receiving and processing SPS signals  338  and  378 , respectively. The SPS receivers  330  and  370  request information and operations as appropriate from the other systems, and performs calculations necessary to determine the apparatus&#39;  302  and  304  positions using measurements obtained by any suitable SPS algorithm. 
     The base station  304  and the network entity  306  each include at least one network interfaces  380  and  390  for communicating with other network entities. For example, the network interfaces  380  and  390  (e.g., one or more network access ports) may be configured to communicate with one or more network entities via a wire-based or wireless backhaul connection. In some aspects, the network interfaces  380  and  390  may be implemented as transceivers configured to support wire-based or wireless signal communication. This communication may involve, for example, sending and receiving: messages, parameters, or other types of information. 
     The apparatuses  302 ,  304 , and  306  also include other components that may be used in conjunction with the operations as disclosed herein. The UE  302  includes processor circuitry implementing a processing system  332  for providing functionality relating to, for example, false base station (FBS) detection as disclosed herein and for providing other processing functionality. The base station  304  includes a processing system  384  for providing functionality relating to, for example, FBS detection as disclosed herein and for providing other processing functionality. The network entity  306  includes a processing system  394  for providing functionality relating to, for example, FBS detection as disclosed herein and for providing other processing functionality. In an aspect, the processing systems  332 ,  384 , and  394  may include, for example, one or more general purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGA), or other programmable logic devices or processing circuitry. 
     The apparatuses  302 ,  304 , and  306  include memory circuitry implementing memory components  340 ,  386 , and  396  (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). In some cases, the apparatuses  302 ,  304 , and  306  may include positioning modules  342 ,  388  and  389 , respectively. The positioning modules  342 ,  388  and  389  may be hardware circuits that are part of or coupled to the processing systems  332 ,  384 , and  394 , respectively, that, when executed, cause the apparatuses  302 ,  304 , and  306  to perform the functionality described herein. Alternatively, the positioning modules  342 ,  388  and  389  may be memory modules (as shown in  FIGS. 3A-C ) stored in the memory components  340 ,  386 , and  396 , respectively, that, when executed by the processing systems  332 ,  384 , and  394 , cause the apparatuses  302 ,  304 , and  306  to perform the functionality described herein. 
     The UE  302  may include one or more sensors  344  coupled to the processing system  332  to provide movement and/or orientation information that is independent of motion data derived from signals received by the WWAN transceiver  310 , the WLAN transceiver  320 , and/or the GPS receiver  330 . By way of example, the sensor(s)  344  may include an accelerometer (e.g., a micro-electrical mechanical systems (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric pressure altimeter), and/or any other type of movement detection sensor. Moreover, the sensor(s)  344  may include a plurality of different types of devices and combine their outputs in order to provide motion information. For example, the sensor(s)  344  may use a combination of a multi-axis accelerometer and orientation sensors to provide the ability to compute positions in 2D and/or 3D coordinate systems. 
     In addition, the UE  302  includes a user interface  346  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  304  and  306  may also include user interfaces. 
     Referring to the processing system  384  in more detail, in the downlink, IP packets from the network entity  306  may be provided to the processing system  384 . The processing system  384  may implement functionality for an 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  384  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  354  and the receiver  352  may implement Layer-1 functionality associated with various signal processing functions. Layer-1, 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  354  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)). The coded and modulated symbols may then be split into parallel streams. 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. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE  302 . Each spatial stream may then be provided to one or more different antennas  356 . The transmitter  354  may modulate an RF carrier with a respective spatial stream for transmission. 
     At the UE  302 , the receiver  312  receives a signal through its respective antenna(s)  316 . The receiver  312  recovers information modulated onto an RF carrier and provides the information to the processing system  332 . The transmitter  314  and the receiver  312  implement Layer-1 functionality associated with various signal processing functions. The receiver  312  may perform spatial processing on the information to recover any spatial streams destined for the UE  302 . If multiple spatial streams are destined for the UE  302 , they may be combined by the receiver  312  into a single OFDM symbol stream. The receiver  312  then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station  304 . 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  304  on the physical channel. The data and control signals are then provided to the processing system  332 , which implements Layer-3 and Layer-2 functionality. 
     In the UL, the processing system  332  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  332  is also responsible for error detection. 
     Similar to the functionality described in connection with the DL transmission by the base station  304 , the processing system  332  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  304  may be used by the transmitter  314  to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the transmitter  314  may be provided to different antenna(s)  316 . The transmitter  314  may modulate an RF carrier with a respective spatial stream for transmission. 
     The UL transmission is processed at the base station  304  in a manner similar to that described in connection with the receiver function at the UE  302 . The receiver  352  receives a signal through its respective antenna(s)  356 . The receiver  352  recovers information modulated onto an RF carrier and provides the information to the processing system  384 . 
     In the UL, the processing system  384  provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE  302 . IP packets from the processing system  384  may be provided to the core network. The processing system  384  is also responsible for error detection. 
     For convenience, the apparatuses  302 ,  304 , and/or  306  are shown in  FIGS. 3A-C  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  302 ,  304 , and  306  may communicate with each other over data buses  334 ,  382 , and  392 , respectively. The components of  FIGS. 3A-C  may be implemented in various ways. In some implementations, the components of  FIGS. 3A-C  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  310  to  346  may be implemented by processor and memory component(s) of the UE  302  (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  350  to  388  may be implemented by processor and memory component(s) of the base station  304  (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  390  to  396  may be implemented by processor and memory component(s) of the network entity  306  (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  332 ,  384 ,  394 , the transceivers  310 ,  320 ,  350 , and  360 , the memory components  340 ,  386 , and  396 , the positioning modules  342 ,  388  and  389 , etc. 
       FIG. 4A  is a diagram  400  illustrating an example of a DL frame structure, according to aspects of the disclosure.  FIG. 4B  is a diagram  430  illustrating an example of channels within the DL frame structure, according to aspects of the disclosure. Other wireless communications technologies may have a different frame structures and/or different channels. 
     LTE, and in some cases NR, utilizes 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, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (resource block) may be 12 subcarriers (or 180 kHz). Consequently, the nominal FFT size may be equal to 128, 256, 512, 1024, or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively. 
     LTE supports a single numerology (subcarrier spacing, symbol length, etc.). In contrast NR may support multiple numerologies, for example, subcarrier spacing of 15 kHz, 30 kHz, 60 kHz, 120 kHz and 204 kHz or greater may be available. Table 1 provided below lists some various parameters for different NR numerologies. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                   
                   
                 Max. nominal 
               
               
                 Subcarrier 
                   
                 slots/ 
                   
                   
                 Symbol 
                 system BW 
               
               
                 spacing 
                 Symbols/ 
                 sub- 
                 slots/ 
                 slot 
                 duration 
                 (MHz) with 
               
               
                 (kHz) 
                 slot 
                 frame 
                 frame 
                 (ms) 
                 (μs) 
                 4K FFT size 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 15 
                 14 
                 1 
                 10 
                 1 
                 66.7 
                 50 
               
               
                 30 
                 14 
                 2 
                 20 
                 0.5 
                 33.3 
                 100 
               
               
                 60 
                 14 
                 4 
                 40 
                 0.25 
                 16.7 
                 100 
               
               
                 120 
                 14 
                 8 
                 80 
                 0.125 
                 8.33 
                 400 
               
               
                 240 
                 14 
                 16 
                 160 
                 0.0625 
                 4.17 
                 800 
               
               
                   
               
            
           
         
       
     
     In the examples of  FIGS. 4A and 4B , a numerology of 15 kHz is used. Thus, in the time domain, a frame (e.g., 10 ms) is divided into 10 equally sized subframes of 1 ms each, and each subframe includes one time slot. In  FIGS. 4A and 4B , 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. 
     A resource grid may be used to represent time slots, each time slot including one or more time concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)) in the frequency domain. The resource grid is further divided into multiple resource elements (REs). An RE may correspond to one symbol length in the time domain and one subcarrier in the frequency domain. In the numerology of  FIGS. 4A and 4B , for a normal cyclic prefix, an RB may contain 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols (for DL, OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a total of 84 REs. For an extended cyclic prefix, an RB may contain 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme. 
     As illustrated in  FIG. 4A , some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS may include demodulation reference signals (DMRS) and channel state information reference signals (CSI-RS), exemplary locations of which are labeled “R” in  FIG. 4A . 
       FIG. 4B  illustrates an example of various channels within a DL subframe of a frame. The physical downlink control channel (PDCCH) carries DL control information (DCI) within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. The DCI carries information about UL resource allocation (persistent and non-persistent) and descriptions about DL data transmitted to the UE. Multiple (e.g., up to 8) DCIs can be configured in the PDCCH, and these DCIs can have one of multiple formats. For example, there are different DCI formats for UL scheduling, for non-MIMO DL scheduling, for MIMO DL scheduling, and for UL power control. 
     A primary synchronization signal (PSS) is used by a UE to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a PCI. Based on the PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH), which carries an MIB, may be logically grouped with the PSS and SSS to form an SSB (also referred to as an SS/PBCH). The MIB provides a number of RBs in the DL system bandwidth and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and paging messages. 
     In some cases, the DL RS illustrated in  FIG. 4A  may be positioning reference signals (PRS).  FIG. 5  illustrates an exemplary PRS configuration  500  for a cell supported by a wireless node (such as a base station  102 ).  FIG. 5  shows how PRS positioning occasions are determined by a system frame number (SFN), a cell specific subframe offset (Δ PRS )  552 , and the PRS periodicity (T PAA )  520 . Typically, the cell specific PRS subframe configuration is defined by a “PRS Configuration Index” I PRS  included in observed time difference of arrival (OTDOA) assistance data. The PRS periodicity (T PAS )  520  and the cell specific subframe offset (Δ PRS ) are defined based on the PRS configuration index I PRS , as illustrated in Table 2 below. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 PRS configuration 
                 PRS periodicity 
                 PRS subframe offset 
               
               
                 Index I PRS   
                 T PRS  (subframes) 
                 Δ PRS  (subframes) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                  0-159 
                 160 
                 I PRS   
               
               
                 160-479 
                 320 
                 I PRS  − 160  
               
               
                  480-1119 
                 640 
                 I PRS  − 480  
               
               
                 1120-2399 
                 1280 
                 I PRS  − 1120 
               
               
                 2400-2404 
                 5 
                 I PRS  − 2400 
               
               
                 2405-2414 
                 10 
                 I PRS  − 2405 
               
               
                 2415-2434 
                 20 
                 I PRS  − 2415 
               
               
                 2435-2474 
                 40 
                 I PRS  − 2435 
               
               
                 2475-2554 
                 80 
                 I PRS  − 2475 
               
            
           
           
               
               
               
            
               
                 2555-4095 
                 Reserved 
               
               
                   
               
            
           
         
       
     
     A PRS configuration is defined with reference to the SFN of a cell that transmits PRS. PRS instances, for the first subframe of the NPRS downlink subframes comprising a first PRS positioning occasion, may satisfy: 
       (10 ×n   ƒ   +└n   s /2┘  Equation (1)
 
     where n f is the SFN with 0&lt;n ƒ ≤1023, ns is the slot number within the radio frame defined by n ƒ  with 0≤n s ≤19, T PRS  is the PRS periodicity  520 , and Δ PRS  is the cell-specific subframe offset  552 . 
     As shown in  FIG. 5 , the cell specific subframe offset Δ PRS    552  may be defined in terms of the number of subframes transmitted starting from system frame number 0 (Slot ‘Number 0’, marked as slot  550 ) to the start of the first (subsequent) PRS positioning occasion. In the example in  FIG. 5 , the number of consecutive positioning subframes (N PRS ) in each of the consecutive PRS positioning occasions  518   a ,  518   b , and  518   c  equals 4. That is, each shaded block representing PRS positioning occasions  518   a ,  518   b , and  518   c  represents four subframes. 
     In some aspects, when a UE receives a PRS configuration index I PRS  in the OTDOA assistance data for a particular cell, the UE may determine the PRS periodicity T PRS    520  and PRS subframe offset APRS using Table 2. The UE may then determine the radio frame, subframe, and slot when a PRS is scheduled in the cell (e.g., using Equation (1)). The OTDOA assistance data may be determined by, for example, the location server (e.g., location server  230 , LMF  270 ), and includes assistance data for a reference cell, and a number of neighbor cells supported by various base stations. 
     Typically, PRS occasions from all cells in a network that use the same frequency are aligned in time and may have a fixed known time offset (e.g., cell-specific subframe offset  552 ) relative to other cells in the network that use a different frequency. In SFN-synchronous networks, all wireless nodes (e.g., base stations  102 ) may be aligned on both frame boundary and system frame number. Therefore, in SFN-synchronous networks, all cells supported by the various wireless nodes may use the same PRS configuration index for any particular frequency of PRS transmission. On the other hand, in SFN-asynchronous networks, the various wireless nodes may be aligned on a frame boundary, but not system frame number. Thus, in SFN-asynchronous networks the PRS configuration index for each cell may be configured separately by the network so that PRS occasions align in time. 
     A UE may determine the timing of the PRS occasions of the reference and neighbor cells for OTDOA positioning, if the UE can obtain the cell timing (e.g., SFN) of at least one of the cells, e.g., the reference cell or a serving cell. The timing of the other cells may then be derived by the UE based, for example, on the assumption that PRS occasions from different cells overlap. 
     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., 1 or more) consecutive symbol(s)  460  within a slot  430  in the time domain. In a given OFDM symbol  460 , 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). In some designs, 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-4 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 or NR 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 NR, navigation reference signals (NRSs) in 5G, transmitter reference signals (TRSs), cell-specific reference signals (CRSs), channel state information reference signals (CSI-RSs), primary synchronization signals (PSSs), secondary synchronization signals (SSSs), SSB, etc. 
     An SRS is an uplink-only signal that a UE transmits to help the base station obtain the channel state information (CSI) for each user. Channel state information describes how an RF signal propagates from the UE to the base station and represents the combined effect of scattering, fading, and power decay with distance. The system uses the SRS for resource scheduling, link adaptation, massive MIMO, beam management, etc. 
     Several enhancements over the previous definition of SRS have been proposed for SRS for positioning (SRS-P), such as a new staggered pattern within an SRS resource, a new comb type for SRS, new sequences for SRS, a higher number of SRS resource sets per component carrier, and a higher number of SRS resources per component carrier. In addition, the parameters “SpatialRelationInfo” and “PathLossReference” are to be configured based on a DL RS from a neighboring TRP. Further still, one SRS resource may be transmitted outside the active bandwidth part (BWP), and one SRS resource may span across multiple component carriers. Lastly, the UE may transmit through the same transmit beam from multiple SRS resources for UL-AoA. All of these are features that are additional to the current SRS framework, which is configured through RRC higher layer signaling (and potentially triggered or activated through MAC control element (CE) or downlink control information (DCI)). 
     As noted above, SRSs in NR are UE-specifically configured reference signals transmitted by the UE used for the purposes of the sounding the uplink radio channel. Similar to CSI-RS, such sounding provides various levels of knowledge of the radio channel characteristics. On one extreme, the SRS can be used at the gNB simply to obtain signal strength measurements, e.g., for the purposes of UL beam management. On the other extreme, SRS can be used at the gNB to obtain detailed amplitude and phase estimates as a function of frequency, time and space. In NR, channel sounding with SRS supports a more diverse set of use cases compared to LTE (e.g., downlink CSI acquisition for reciprocity-based gNB transmit beamforming (downlink MIMO); uplink CSI acquisition for link adaptation and codebook/non-codebook based precoding for uplink MIMO, uplink beam management, etc.). 
     The SRS can be configured using various options. The time/frequency mapping of an SRS resource is defined by the following characteristics.
         Time duration N symb   SRS —The time duration of an SRS resource can be 1, 2, or 4 consecutive OFDM symbols within a slot, in contrast to LTE which allows only a single OFDM symbol per slot.   Starting symbol location 1 0 —The starting symbol of an SRS resource can be located anywhere within the last 6 OFDM symbols of a slot provided the resource does not cross the end-of-slot boundary.   Repetition factor R—For an SRS resource configured with frequency hopping, repetition allows the same set of subcarriers to be sounded in R consecutive OFDM symbols before the next hop occurs (as used herein, a “hop” refers to specifically to a frequency hop). For example, values of R are 1, 2, 4 where R≤N symb   SRS .   Transmission comb spacing K TC  and comb offset k TC —An SRS resource may occupy resource elements (REs) of a frequency domain comb structure, where the comb spacing is either 2 or 4 REs like in LTE. Such a structure allows frequency domain multiplexing of different SRS resources of the same or different users on different combs, where the different combs are offset from each other by an integer number of REs. The comb offset is defined with respect to a PRB boundary, and can take values in the range 0,1, . . . ,K TC −1 REs. Thus, for comb spacing K TC =2, there are 2 different combs available for multiplexing if needed, and for comb spacing K TC =4, there are 4 different available combs.   Periodicity and slot offset for the case of periodic/semi-persistent SRS.   Sounding bandwidth within a bandwidth part.       

     For low latency positioning, a gNB may trigger a UL SRS-P via a DCI (e.g., transmitted SRS-P may include repetition or beam-sweeping to enable several gNBs to receive the SRS-P). Alternatively, the gNB may send information regarding aperiodic PRS transmission to the UE (e.g., this configuration may include information about PRS from multiple gNBs to enable the UE to perform timing computations for positioning (UE-based) or for reporting (UE-assisted). While various embodiments of the present disclosure relate to DL PRS-based positioning procedures, some or all of such embodiments may also apply to UL SRS-P-based positioning procedures. 
     Note that the terms “sounding reference signal”, “SRS” and “SRS-P” may sometimes refer to specific reference signals that are used for positioning in LTE or NR systems. However, as used herein, unless otherwise indicated, the terms “sounding reference signal”, “SRS” and “SRS-P” refer to any type of reference signal that can be used for positioning, such as but not limited to, SRS signals in LTE or NR, navigation reference signals (NRSs) in 5G, transmitter reference signals (TRSs), random access channel (RACH) signals for positioning (e.g., RACH preambles, such as Msg-1 in 4-Step RACH procedure or Msg-A in 2-Step RACH procedure), etc. 
     3GPP Rel. 16 introduced various NR positioning aspects directed to increase location accuracy of positioning schemes that involve measurement(s) associated with one or more UL or DL PRSs (e.g., higher bandwidth (BW), FR2 beam-sweeping, angle-based measurements such as Angle of Arrival (AoA) and Angle of Departure (AoD) measurements, multi-cell Round-Trip Time (RTT) measurements, etc.). If latency reduction is a priority, then UE-based positioning techniques (e.g., DL-only techniques without UL location measurement reporting) are typically used. However, if latency is less of a concern, then UE-assisted positioning techniques can be used, whereby UE-measured data is reported to a network entity (e.g., location server  230 , LMF  270 , etc.). Latency associated UE-assisted positioning techniques can be reduced somewhat by implementing the LMF in the RAN. 
     Layer-3 (L3) signaling (e.g., RRC or Location Positioning Protocol (LPP)) is typically used to transport reports that comprise location-based data in association with UE-assisted positioning techniques. L3 signaling is associated with relatively high latency (e.g., above 100 ms) compared with Layer-1 (L1, or PHY layer) signaling or Layer-2 (L2, or MAC layer) signaling. In some cases, lower latency (e.g., less than 100 ms, less than 10 ms, etc.) between the UE and the RAN for location-based reporting may be desired. In such cases, L3 signaling may not be capable of reaching these lower latency levels. L3 signaling of positioning measurements may comprise any combination of the following:
         One or multiple TOA, TDOA, RSRP or Rx-Tx measurements,   One or multiple AoA/AoD (e.g., currently agreed only for gNB→LMF reporting DL AoA and UL AoD) measurements,   One or multiple Multipath reporting measurements, e.g., per-path ToA, RSRP, AoA/AoD (e.g., currently only per-path ToA allowed in LTE)   One or multiple motion states (e.g., walking, driving, etc.) and trajectories (e.g., currently for UE), and/or   One or multiple report quality indications.       

     More recently, L1 and L2 signaling has been contemplated for use in association with PRS-based reporting. For example, L1 and L2 signaling is currently used in some systems to transport CSI reports (e.g., reporting of Channel Quality Indications (CQIs), Precoding Matrix Indicators (PMIs), Layer Indicators (Lis), L1-RSRP, etc.). CSI reports may comprise a set of fields in a pre-defined order (e.g., defined by the relevant standard). A single UL transmission (e.g., on PUSCH or PUCCH) may include multiple reports, referred to herein as ‘sub-reports’, which are arranged according to a pre-defined priority (e.g., defined by the relevant standard). In some designs, the pre-defined order may be based on an associated sub-report periodicity (e.g., aperiodic/semi-persistent/periodic (A/SP/P) over PUSCH/PUCCH), measurement type (e.g., L1-RSRP or not), serving cell index (e.g., in carrier aggregation (CA) case), and reportconfigID. With 2-part CSI reporting, the part 1s of all reports are grouped together, and the part 2s are grouped separately, and each group is separately encoded (e.g., part 1 payload size is fixed based on configuration parameters, while part 2 size is variable and depends on configuration parameters and also on associated part 1 content). A number of coded bits/symbols to be output after encoding and rate-matching is computed based on a number of input bits and beta factors, per the relevant standard. Linkages (e.g., time offsets) are defined between instances of RSs being measured and corresponding reporting. In some designs, CSI-like reporting of PRS-based measurement data using L1 and L2 signaling may be implemented. 
       FIG. 6  illustrates an exemplary wireless communications system  600  according to various aspects of the disclosure. In the example of  FIG. 6 , a UE  604 , which may correspond to any of the UEs described above with respect to  FIG. 1  (e.g., UEs  104 , UE  182 , UE  190 , 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  604  may communicate wirelessly with a plurality of base stations  602   a - d  (collectively, base stations  602 ), which may correspond to any combination of base stations  102  or  180  and/or WLAN AP  150  in  FIG. 1 , 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  600  (i.e., the base stations locations, geometry, etc.), the UE  604  may determine its position, or assist in the determination of its position, in a predefined reference coordinate system. In an aspect, the UE  604  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. 6  illustrates one UE  604  and four base stations  602 , as will be appreciated, there may be more UEs  604  and more or fewer base stations  602 . 
     To support position estimates, the base stations  602  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  604  in their coverage areas to enable a UE  604  to measure reference RF signal timing differences (e.g., OTDOA or reference signal time difference (RSTD)) between pairs of network nodes and/or to identify the beam that best excite the LOS or shortest radio path between the UE  604  and the transmitting base stations  602 . 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  602 , 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  602 , a cell of a base station  602 , a remote radio head, an antenna of a base station  602 , where the locations of the antennas of a base station  602  are distinct from the location of the base station  602  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  230 ) may send assistance data to the UE  604  that includes an identification of one or more neighbor cells of base stations  602  and configuration information for reference RF signals transmitted by each neighbor cell. Alternatively, the assistance data can originate directly from the base stations  602  themselves (e.g., in periodically broadcasted overhead messages, etc.). Alternatively, the UE  604  can detect neighbor cells of base stations  602  itself without the use of assistance data. The UE  604  (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)  602  or antenna(s) that transmitted the reference RF signals that the UE  604  measured), the UE  604  or the location server can determine the distance between the UE  604  and the measured network nodes and thereby calculate the location of the UE  604 . 
     The term “position estimate” is used herein to refer to an estimate of a position for a UE  604 , 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  602 ) 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  604 ) and a neighbor base station whose reference RF signals the UE is measuring. Thus,  FIG. 6  illustrates an aspect in which base stations  602   a  and  602   b  form a DAS/RRH  620 . For example, the base station  602   a  may be the serving base station of the UE  604  and the base station  602   b  may be a neighbor base station of the UE  604 . As such, the base station  602   b  may be the RRH of the base station  602   a . The base stations  602   a  and  602   b  may communicate with each other over a wired or wireless link  622 . 
     To accurately determine the position of the UE  604  using the OTDOAs and/or RSTDs between RF signals received from pairs of network nodes, the UE  604  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  604  and a network node (e.g., base station  602 , 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. 6  illustrates a number of LOS paths  610  and a number of NLOS paths  612  between the base stations  602  and the UE  604 . Specifically,  FIG. 6  illustrates base station  602   a  transmitting over an LOS path  610   a  and an NLOS path  612   a , base station  602   b  transmitting over an LOS path  610   b  and two NLOS paths  612   b , base station  602   c  transmitting over an LOS path  610   c  and an NLOS path  612   c , and base station  602   d  transmitting over two NLOS paths  612   d . As illustrated in  FIG. 6 , each NLOS path  612  reflects off some object  630  (e.g., a building). As will be appreciated, each LOS path  610  and NLOS path  612  transmitted by a base station  602  may be transmitted by different antennas of the base station  602  (e.g., as in a MIMO system), or may be transmitted by the same antenna of a base station  602  (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  602  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  610  (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  612 . 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  602  uses beamforming to transmit RF signals, the beams of interest for data communication between the base station  602  and the UE  604  will be the beams carrying RF signals that arrive at UE  604  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  610 ). 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. 7 , in some cases, the signal strength of RF signals on the LOS path  610  may be weaker (e.g., due to obstructions) than the signal strength of RF signals on an NLOS path  612 , over which the RF signals arrive later due to propagation delay. 
       FIG. 7  illustrates an exemplary wireless communications system  700  according to various aspects of the disclosure. In the example of  FIG. 7 , a UE  704 , which may correspond to UE  604  in  FIG. 6 , 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  704  may communicate wirelessly with a base station  702 , which may correspond to one of base stations  602  in  FIG. 6 , using RF signals and standardized protocols for the modulation of the RF signals and the exchange of information packets. 
     As illustrated in  FIG. 7 , the base station  702  is utilizing beamforming to transmit a plurality of beams  711 - 715  of RF signals. Each beam  711 - 715  may be formed and transmitted by an array of antennas of the base station  702 . Although  FIG. 7  illustrates a base station  702  transmitting five beams  711 - 715 , 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  711 - 715  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  711 - 715  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. 7 , the UE  704  receives an NLOS data stream  723  of RF signals transmitted on beam  713  and an LOS data stream  724  of RF signals transmitted on beam  714 . Although  FIG. 7  illustrates the NLOS data stream  723  and the LOS data stream  724  as single lines (dashed and solid, respectively), as will be appreciated, the NLOS data stream  723  and the LOS data stream  724  may each comprise multiple rays (i.e., a “cluster”) by the time they reach the UE  704  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  704 ) 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. 7 , the NLOS data stream  723  is not originally directed at the UE  704 , although, as will be appreciated, it could be, as are the RF signals on the NLOS paths  612  in  FIG. 6 . However, it is reflected off a reflector  740  (e.g., a building) and reaches the UE  704  without obstruction, and therefore, may still be a relatively strong RF signal. In contrast, the LOS data stream  724  is directed at the UE  704  but passes through an obstruction  730  (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  724  is weaker than the NLOS data stream  723 , the LOS data stream  724  will arrive at the UE  704  before the NLOS data stream  723  because it follows a shorter path from the base station  702  to the UE  704 . 
     As noted above, the beam of interest for data communication between a base station (e.g., base station  702 ) and a UE (e.g., UE  704 ) 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  714 ). That is, even if beam  713  (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  713  may not be as reliably detectable (compared to that from beam  714 ), 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. 7 , where the UE  704  is engaged in a data communication session with the base station  702  (e.g., where the base station  702  is the serving base station for the UE  704 ) and not simply attempting to measure reference RF signals transmitted by the base station  702 , the beam of interest for the data communication session may be the beam  713 , as it is carrying the unobstructed NLOS data stream  723 . The beam of interest for position estimation, however, would be the beam  714 , as it carries the strongest LOS data stream  724 , despite being obstructed. 
       FIG. 8A  is a graph  800 A showing the RF channel response at a receiver (e.g., UE  704 ) over time according to aspects of the disclosure. Under the channel illustrated in  FIG. 8A , 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. 8A , 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  724 . The third cluster at time T3 is comprised of the strongest RF signals, and may correspond to the NLOS data stream  723 . Seen from the transmitter&#39;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. 8B  is a diagram  800 B illustrating this separation of clusters in AoD. The RF signal transmitted in AoD range  802   a  may correspond to one cluster (e.g., “Cluster 1”) in  FIG. 8A , and the RF signal transmitted in AoD range  802   b  may correspond to a different cluster (e.g., “Cluster 3 ”) in  FIG. 8A . Note that although AoD ranges of the two clusters depicted in  FIG. 8B  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. 8A  illustrates clusters of two to five channel taps (or “peaks”), as will be appreciated, the clusters may have more or fewer than the illustrated number of channel taps. 
     RAN1 NR may define UE measurements on DL reference signals (e.g., for serving, reference, and/or neighboring cells) applicable for NR positioning, including DL reference signal time difference (RSTD) measurements for NR positioning, DL RSRP measurements for NR positioning, and UE Rx-Tx (e.g., a hardware group delay from signal reception at UE receiver to response signal transmission at UE transmitter, e.g., for time difference measurements for NR positioning, such as RTT). 
     RAN1 NR may define gNB measurements based on UL reference signals applicable for NR positioning, such as relative UL time of arrival (RTOA) for NR positioning, UL AoA measurements (e.g., including Azimuth and Zenith Angles) for NR positioning, UL RSRP measurements for NR positioning, and gNB Rx-Tx (e.g., a hardware group delay from signal reception at gNB receiver to response signal transmission at gNB transmitter, e.g., for time difference measurements for NR positioning, such as RTT). 
       FIG. 9  is a diagram  900  showing exemplary timings of RTT measurement signals exchanged between a base station  902  (e.g., any of the base stations described herein) and a UE  904  (e.g., any of the UEs described herein), according to aspects of the disclosure. In the example of  FIG. 9 , the base station  902  sends an RTT measurement signal  910  (e.g., PRS, NRS, CRS, CSI-RS, etc.) to the UE  904  at time t 1 . The RTT measurement signal  910  has some propagation delay T Prop  as it travels from the base station  902  to the UE  904 . At time t 2  (the ToA of the RTT measurement signal  910  at the UE  904 ), the UE  904  receives/measures the RTT measurement signal  910 . After some UE processing time, the UE  904  transmits an RTT response signal  920  at time t 3 . After the propagation delay T Prop , the base station  902  receives/measures the RTT response signal  920  from the UE  904  at time t 4  (the ToA of the RTT response signal  920  at the base station  902 ). 
     In order to identify the ToA (e.g., t 2 ) of a reference signal (e.g., an RTT measurement signal  910 ) transmitted by a given network node (e.g., base station  902 ), the receiver (e.g., UE  904 ) 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 choose 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  920  may explicitly include the difference between time t 3  and time t 2  (i.e., T Rx→Tx    912 ). Using this measurement and the difference between time t 4  and time t 1  (i.e., T Tx→Rx    922 ), the base station  902  (or other positioning entity, such as location server  230 , LMF  270 ) can calculate the distance to the UE  904  as: 
     
       
         
           
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     where c is the speed of light. While not illustrated expressly in  FIG. 9 , an additional source of delay or error may be due to UE and gNB hardware group delay for position location. 
     Various parameters associated with positioning can impact power consumption at the UE. Knowledge of such parameters can be used to estimate (or model) the UE power consumption. By accurately modeling the power consumption of the UE, various power saving features and/or performance enhancing features can be utilized in a predictive manner so as to improve the user experience. 
     An additional source of delay or error is due to UE and gNB hardware group delay for position location.  FIG. 10  illustrates a diagram  1000  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. 10  is similar in some respects to  FIG. 9 . However, in FIG.  10 , the UE and gNB hardware group delay (which is primarily due to internal hardware delays between a baseband (BB) component and antenna (ANT) at the UE and gNB) is shown with respect  1002 - 1008 . As will be appreciated, both Tx-side and Rx-side path-specific or beam-specific delays impact the RTT measurement. Hardware group delays such as  1002 - 1008  can contribute to timing errors and/or calibration errors that can impact RTT as well as other measurements such as TDOA, RSTD, and so on, which in turn can impact positioning performance. For example, in some designs, 10 nsec of error will introduce the 3 meter of error in the final fix. 
       FIG. 11  illustrates an exemplary wireless communications system  1100  according to aspects of the disclosure. In the example of  FIG. 11 , a UE  1104  (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, via a multi-RTT positioning scheme. The UE  1104  may communicate wirelessly with a plurality of base stations  1102 - 1 ,  1102 - 2 , and  1102 - 3  (collectively, base stations  1102 , 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  1100  (i.e., the base stations&#39; locations, geometry, etc.), the UE  1104  may determine its position, or assist in the determination of its position, in a predefined reference coordinate system. In an aspect, the UE  1104  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. 11  illustrates one UE  1104  and three base stations  1102 , as will be appreciated, there may be more UEs  1104  and more base stations  1102 . 
     To support position estimates, the base stations  1102  may be configured to broadcast reference RF signals (e.g., PRS, NRS, CRS, TRS, CSI-RS, PSS, SSS, etc.) to UEs  1104  in their coverage area to enable a UE  1104  to measure characteristics of such reference RF signals. For example, the UE  1104  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  1102  and may use the RTT positioning method to report these 
     ToAs (and additional information) back to the serving base station  1102  or another positioning entity (e.g., location server  230 , LMF  270 ). 
     In an aspect, although described as the UE  1104  measuring reference RF signals from a base station  1102 , the UE  1104  may measure reference RF signals from one of multiple cells supported by a base station  1102 . Where the UE  1104  measures reference RF signals transmitted by a cell supported by a base station  1102 , the at least two other reference RF signals measured by the UE  1104  to perform the RTT procedure would be from cells supported by base stations  1102  different from the first base station  1102  and may have good or poor signal strength at the UE  1104 . 
     In order to determine the position (x, y) of the UE  1104 , the entity determining the position of the UE  1104  needs to know the locations of the base stations  1102 , which may be represented in a reference coordinate system as (x k , y k ), where k=1, 2, 3 in the example of  FIG. 11 . Where one of the base stations  1102  (e.g., the serving base station) or the UE  1104  determines the position of the UE  1104 , the locations of the involved base stations  1102  may be provided to the serving base station  1102  or the UE  1104  by a location server with knowledge of the network geometry (e.g., location server  230 , LMF  270 ). Alternatively, the location server may determine the position of the UE  1104  using the known network geometry. 
     Either the UE  1104  or the respective base station  1102  may determine the distance (d k , where k=1, 2, 3) between the UE  1104  and the respective base station  1102 . In an aspect, determining the RTT  1110  of signals exchanged between the UE  1104  and any base station  1102  can be performed and converted to a distance (d k ). 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  1104  and the base stations  1102  are the same. However, such an assumption may not be true in practice. 
     Once each distance dk is determined, the UE  1104 , a base station  1102 , or the location server (e.g., location server  230 , LMF  270 ) can solve for the position (x, y) of the UE  1104  by using a variety of known geometric techniques, such as, for example, trilateration. From  FIG. 11 , it can be seen that the position of the UE  1104  ideally lies at the common intersection of three semicircles, each semicircle being defined by radius dk and center (x k , y k ), where k=1, 2, 3. 
     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  1104  from the location of a base station  1102 ). The intersection of the two directions at or near the point (x, y) can provide another estimate of the location for the UE  1104 . 
     A position estimate (e.g., for a UE  1104 ) 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. 12  illustrates is a diagram  1200  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,  1202 - 1204  of  FIG. 12  denote portions of frame delay that are associated with a Rx-Tx differences as measured at the gNB and UE, respectively. 
     As will be appreciated from the disclosure above, NR native positioning technologies supported in 5G NR include DL-only positioning schemes (e.g., DL-TDOA, DL-AoD, etc.), UL-only positioning schemes (e.g., UL-TDOA, UL-AoA), and DL+UL positioning schemes (e.g., RTT with one or more neighboring base stations, or multi-RTT). In addition, Enhanced Cell-ID (E-CID) based on radio resource management (RRM) measurements is supported in 5G NR Rel-16. 
     Differential RTT is another positioning scheme, whereby a difference of two RTT measurements (or measurement ranges) is used to generate a positioning estimate for a UE. As an example, 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. 
     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  FIGS. 6-7 ). Otherwise, in some designs, differential RTT is performed so that 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). 
     As noted above, in some designs, angular measurements associated with reference signals for positioning (RS-Ps) may be used to improve positioning accuracy of a target UE. In some designs, UL-AoA measurements may be used for network-based positioning solutions (e.g., a position estimation entity at a network, such as LMF in RAN or core network, location server, etc. receives measurement information and derives a positioning estimate of the target UE). In some designs, DL-AoD measurements may be used for UE-based and network-based (including UE-assisted) positioning solutions. 
     Aspects of the disclosure are directed to an angular measurement (e.g., AoA, AoD, etc.) calibration scheme. For example, a reference angular (e.g., AoA, AoD, etc.) measurement may be used to cancel out (or at least reduce) an angular bias of an angular measurement to/from a target UE and a gNB involved in a positioning session with the target UE. Such aspects may provide various technical advantages, such as more accurate UE position estimation. 
       FIG. 13  illustrates an exemplary process  1300  of wireless communication, according to aspects of the disclosure. In an aspect, the process  1300  may be performed by a communications device, which may correspond to a UE such as UE  302  (e.g., for UE-based positioning), a BS or gNB such as BS  304  (e.g., for LMF integrated in RAN, or by a gNB that formats data that is forwarded on to a remote LMF), or a network entity  306  (e.g., core network component such as LMF, a position estimation entity, a location server, etc.). 
     At  1310 , the communications device (e.g., receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc.) obtains a residual AoA bias associated with a first AoA measurement of a RS-P transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device. For example, the RS-P may be measured at the first base station. In an example, if the wireless reference node corresponds to a reference UE (e.g., a UE whose location was recently obtained, a static or semi-static UE, etc.), the RS-P may correspond to an UL-SRS-P. In other designs, if the wireless reference node corresponds to a second base station, the RS-P may correspond to a PRS (e.g., configured similar to a DL-PRS, or a new PRS configuration for BS-to-BS positioning signaling). As will be described below in more detail, the residual AoA bias may either be received at the communications device from an external entity at  1310 , or else information by which the residual AoA bias may be derived is received at the communications device and then used to derive the residual AoA bias at  1310 . A means for obtaining the residual AoA bias at  1310  may include receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc. 
     At  1320 , the communications device (e.g., receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc.) obtains a second AoA measurement associated with an uplink signal transmitted from a UE to the first base station. In some designs, the uplink signal may correspond to a physical random access channel (PRACH) signal (e.g., Msg-1 PRACH preamble, Msg-3 PUSCH or PUCCH, etc.). In some designs, the uplink signal corresponds to SRS (e.g., such as an SRS for positioning or UL-SRS-P). For example, the UE may correspond to a target UE for which a positioning fix is performed. In some designs, the communications device may correspond to the first base station itself, in which case the second AoA measurement is obtained by direct measurement. In other designs, the communications device may correspond to another entity (e.g., LMF, UE for UE-based positioning, etc.), in which case the second AoA measurement is obtained via signaling. A means for obtaining the second AoA measurement at  1320  may include receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc. 
     At  1330 , the communications device (e.g., positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , etc.) calibrates the second AoA measurement based on the residual AoA bias. A means for calibrating the second AoA measurement at  1330  may include positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , etc. 
     Referring to  FIG. 13 , in some designs as noted above, the residual AoA bias is received from the first base station. In other designs, the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Referring to  FIG. 13 , in some designs, the communications device corresponds to a position estimation entity (e.g., LMF in RAN or core network for network-based positioning or UE-assisted positioning, UE for UE-based positioning, etc.). In this case, the communications device may determine a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Referring to  FIG. 13 , in some designs, the communications device corresponds to the first base station. In this case, the first base station may transmit the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Referring to  FIG. 13 , in some designs, the wireless reference node may correspond to a second base station or a reference UE. 
     Referring to  FIG. 13 , in some designs, the RS-P may correspond to a single symbol positioning reference signal (PRS) or a multi-symbol PRS (e.g., a legacy Rel. 16 PRS). 
     Referring to  FIG. 13 , in some designs, the first AoA measurement may be triggered periodically, aperiodically, or on-demand.  FIG. 14  illustrates a gNB configuration  1400  in accordance with an aspect of the disclosure. In an example, a periodic, aperiodic or on-demand request for AoA calibration may be sent to the wireless reference node (e.g., reference gNB in this case) directly through Xn or F1 (e.g., central unit (CU)/distributed unit (DU) split). The LMF may signal the time/frequency allocation (and potentially the beam information) of a specific requested PRS to the first base station. In some designs, this PRS may be QCLed with the UL signal (e.g., UL-SRS-P) of  1320 . 
     Referring to  FIG. 13 , in some designs, the wireless reference node may be selected from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. For example, since the AoA bias may vary across the genie angle or even UE location, the LMF may select a wireless reference node (e.g., reference gNB or UE) that is most aligned with the UE in angle domain. In another example, since the bias in the frequency domain is not constant, the LMF may request the reference node (e.g., gNB or UE) to send positioning RS that is close in frequency domain with the UL signal (e.g., UL-SRS-P) transmitted by UE at  1320 . Alternatively, the LMF may select a reference node (e.g., gNB or UE) based on its carrier frequency for positioning RS transmission. In some designs, the above-noted selection may be based upon a lookup operation in a lookup table (e.g., which may be configured at a location area granularity). 
     Referring to  FIG. 13 , in some designs, the first AoA measurement may include a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or the second AoA measurement may include a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
       FIG. 15  illustrates an example implementation  1500  of the process  1300  of  FIG. 13  in accordance with an aspect of the disclosure. In  FIG. 15 , a base station  1502  (e.g., corresponding to the first base station referenced in the description of  FIG. 13 ), a first target UE  1504  (or UE  1 ), a first wireless reference node  1506 , a second wireless reference node  1508 , and a second target UE (or UE  2 ) are depicted. The first wireless reference node  1506  and the second wireless reference node  1508  may alternatively be denoted as wireless reference nodes 1 and 2, respectively, and either node may correspond to the wireless reference node as referenced with respect to the process  1300  of  FIG. 13 . In  FIG. 15 , target UE  1504  transmits UL signal (e.g., UL-SRS-P)  1512  to the base station  1502 , the first wireless reference node  1506  transmits RS-P  1514  (e.g., PRS, UL-SRS-P, a new PRS type, etc.) to the base station  1502 , the second wireless reference node  1508  transmits RS-P  1516  (e.g., PRS, UL-SRS-P, a new PRS type, etc.) to the base station  1502 , and target UE  1510  transmits UL signal (e.g., UL-SRS-P)  1518  to the base station  1502 . The base station  1502  measures AoA with respect to each of the above-noted RS-Ps  1512 - 1518 . In some designs, an AoA bias determined from the AoA of the RS-P  1514  may be used for calibration of the AoA of the UL signal (e.g., UL-SRS-P)  1512 , and an AoA bias determined from the AoA of the RS-P  1516  may be used for calibration of the AoA of the UL signal (e.g., UL-SRS-P)  1518 . In this case, the first wireless reference node  1506  may be selected for calibration of the target UE  1504  due to their alignment in terms of angle, location, frequency domain, etc., and likewise the second wireless reference node  1508  may be selected for calibration of the target UE  1510  due to their alignment in terms of angle, location, frequency domain, etc. 
       FIG. 16  illustrates an example implementation  1600  of the process  1300  of  FIG. 13  in accordance with another aspect of the disclosure.  1602 - 1618  of  FIG. 16  are similar to  1502 - 1518  of  FIG. 15 , respectively, except that the first wireless reference node  1506  and the second wireless reference node  1508  are more specifically illustrated as gNBs  1606  and  1608 , respectively, in  FIG. 16 .  FIGS. 15-16  are otherwise the same, and as such  FIG. 16  will not be discussed further for the sake of brevity. 
       FIG. 17  illustrates an example implementation  1700  of the process  1300  of  FIG. 13  in accordance with another aspect of the disclosure.  1702 - 1718  of  FIG. 17  are similar to  1502 - 1518  of  FIG. 15 , respectively, except that the first wireless reference node  1506  and the second wireless reference node  1508  are more specifically illustrated as reference UEs  1706  and  1708 , respectively, in  FIG. 17 .  FIGS. 15 and 17  are otherwise the same, and as such  FIG. 17  will not be discussed further for the sake of brevity. 
     While  FIGS. 13-17  are directed to aspects related to AoA, calibration of angular bias may also be implemented with respect to AoD, as will be described below with respect to  FIGS. 18-21 . 
       FIG. 18  illustrates an exemplary process  1800  of wireless communication, according to aspects of the disclosure. In an aspect, the process  1800  may be performed by a communications device, which may correspond to a UE such as UE  302  (e.g., for UE-based positioning), a BS or gNB such as BS  304  (e.g., for LMF integrated in RAN, or by a gNB that formats data that is forwarded on to a remote LMF), or a network entity  306  (e.g., core network component such as LMF, a position estimation entity, a location server, etc.). 
     At  1810 , the communications device (e.g., receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc.) a residual AoD bias associated with a first AoD measurement of a RS-P transmitted from a first base station to a wireless reference node with a known location. For example, the RS-P may be measured at wireless reference node. In an example, if the wireless reference node corresponds to a reference UE (e.g., a UE whose location was recently obtained, a static or semi-static UE, etc.), the RS-P may correspond to a DL-PRS. In other designs, if the wireless reference node corresponds to a second base station, the RS-P may correspond to a PRS (e.g., configured similar to a DL-PRS, or a new PRS configuration for BS-to-BS positioning signaling). As will be described below in more detail, the residual AoD bias may either be received at the communications device from an external entity at  1810 , or else information by which the residual AoD bias may be derived is received at the communications device and then used to derive the residual AoD bias at  1810 . A means for obtaining the residual AoD bias at  1810  may include receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc. 
     At  1820 , the communications device (e.g., receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc.) obtains a second AoD measurement associated with a downlink signal (e.g., DL-PRS) transmitted from the first base station to a UE. For example, the UE may correspond to a target UE for which a positioning fix is performed. A means for obtaining the second AoD measurement at  1820  may include receiver  312  or  322 , receiver  352  or  362 , positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , network interface(s)  380  or  390 , etc. 
     At  1830 , the communications device (e.g., positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , etc.) calibrates the second AoD measurement based on the residual AoD bias. A means for calibrating the second AoD measurement at  1830  may include positioning module  342  or  388  or  389 , processing system  334  or  384  or  394 , etc. 
     Referring to  FIG. 18 , in some designs as noted above, the residual AoD bias is received from the first base station or the wireless reference node. In other designs, the first AoD measurement is received from the first base station or the wireless reference node (e.g., relayed from the first base station by the wireless reference node), and the residual AoD bias is derived at the communications device based on the first AoD measurement. For example, in a scenario where the wireless reference node corresponds to a reference gNB, the reference gNB may be equipped with an antenna array so as to perform a digital Rx beam sweep to estimate AoD with a single RS-P (e.g., similar to AoA estimation). In this case, the reference gNB may report the estimated AoD directly to the LMF or location server. In other designs, reference signal received power (RSRP) measurements and beam pattern information are received from the first base station for derivation of the first AoD measurement. In other designs, the beam pattern may be signaled to the wireless reference node from the LMF (e.g., beam pattern sent by first base station to LMF, which then in turn signals the beam pattern to the wireless reference node). 
     Referring to  FIG. 18 , in some designs, the calibration of  1830  is performed in association with UE-based position estimation of the UE. In an example where the calibration of  1830  is performed in association with UE-based position estimation of the UE, the communications device may correspond to the wireless reference node, and the wireless reference node may further transmit, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or RSRP measurements, and/or may receive a beam pattern of the RS-P from which the first AoD measurement is derivable (e.g., from the first base station directly or via the LMF). In another example, the beam pattern is reported by the first base station, but need not be reported from the wireless reference node (e.g., the wireless reference node may instead report RSRP). In an alternative example where the calibration of  1830  is performed in association with UE-based position estimation of the UE, the communications device may correspond to the UE, and the UE may receive RSRP measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or may receive the first AoD measurement (e.g., in this case, both the location of the first base station and the wireless reference node may be signaled to the UE, which is used to derive the genie AoD), or may receive the residual AoD bias (e.g., any of which may be used for the calibration by the UE at  1830 ). In another alternative example where the calibration of  1830  is performed in association with UE-based position estimation of the UE, the communications device may correspond to the UE, and the LMF may transmit, to the UE, the AoD bias which is used by the UE to derive the calibrated second AoD measurement. 
     Referring to  FIG. 18 , in some designs, the communications device corresponds to a position estimation entity (e.g., LMF in RAN or core network for network-based positioning or UE-assisted positioning, UE for UE-based positioning, etc.). In this case, the communications device may determine a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Referring to  FIG. 18 , in some designs, the communications device corresponds to a second base station or a reference UE. 
     Referring to  FIG. 18 , in some designs, the RS-P may correspond to a single symbol positioning reference signal (PRS) or a multi-symbol PRS (e.g., a legacy Rel. 16 PRS). 
     Referring to  FIG. 18 , in some designs, the first AoD measurement may be triggered periodically, aperiodically, or on-demand. In an example, a periodic, aperiodic or on-demand request for AoD calibration may be sent to the wireless reference node (e.g., reference gNB in this case) directly through Xn or F1 (e.g., central unit (CU)/distributed unit (DU) split). The LMF may signal the time/frequency allocation (and potentially the beam information) of a specific requested PRS to the first base station. In some designs, this PRS may be QCLed with the PRS beams for UE DL-AoD estimation. 
     Referring to  FIG. 18 , in some designs, the wireless reference node may be selected from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. For example, since the AoD bias may vary across the genie angle or even UE location, the LMF may select a wireless reference node (e.g., reference gNB or UE) that is most aligned with the UE in angle domain. In another example, since the bias in the frequency domain is not constant, the LMF may request the reference node (e.g., gNB or UE) to send positioning RS that is close in frequency domain with the downlink signal (e.g., DL-PRS) transmitted to the UE at  1820 . Alternatively, the LMF may select a reference node (e.g., gNB or UE) based on its carrier frequency for positioning RS transmission. In some designs, the above-noted selection may be based upon a lookup operation in a lookup table (e.g., which may be configured at a location area granularity). 
     Referring to  FIG. 18 , in some designs, the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Referring to  FIG. 18 , as noted above, the wireless reference node may be capable of AoD estimation based on a single RS-P if equipped with an antenna array that supports digital Rx beam sweeping (similar to AoA estimation). A wireless reference node with such capabilities would typically correspond to a base station or gNB. wireless reference node base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. In this case, RSRP measurements need not factored into the AoD estimation. 
     Referring to  FIG. 18 , in some designs, various mechanisms may be used to support UE-based positioning using DL-AoD with OTA calibration, as will now be described. 
     In a first example, the UE may receive (e.g., from LMF) a beam pattern of the positioning RS transmitted from the first base station towards the wireless reference node. The LMF may further signal, to the UE, the RSRP measurement(s) reported by the wireless reference node. 
     In a second example, the wireless reference node may obtain a beam pattern of the positioning RS transmitted from the first base station towards the wireless reference node. The wireless reference node may estimate its DL-AoD based on the positioning RS measurement and the corresponding beam pattern information. The wireless reference node may feedback the estimated DL-AoD to LMF, and then location server (or LMF) may derive the DL-AoD bias. Alternatively, the wireless reference node may directly estimate the DL-AoD bias and then report it the location server. In a further example, the LMF may signal the DL-AoD bias to the UE through serving gNB. In the signaling, the bias signaling may include a time stamp and absolute AoD associated with the respective reference AoD measurement. 
     In a third example, the wireless reference node may report the RSRP measurement(s) to LMF. The LMF may then signal the DL-AoD bias to the UE through serving gNB. In the signaling, the bias signaling may include the time stamp and absolute AoD associated with the respective reference AoD measurement. 
     In a fourth example, no assistance data regarding beam pattern is needed. Rather, the wireless reference node (e.g., reference gNB) may report the AoD to the location server or LMF, the location server or LMF signals the AoD bias to the UE. 
       FIG. 19  illustrates an example implementation  1900  of the process  1800  of  FIG. 18  in accordance with an aspect of the disclosure. In  FIG. 19 , a base station  1902  (e.g., corresponding to the first base station referenced in the description of  FIG. 18 ), a first target UE  1904  (or UE  1 ), a first wireless reference node  1906 , a second wireless reference node  1908 , and a second target UE (or UE  2 ) are depicted. The first wireless reference node  1906  and the second wireless reference node  1908  may alternatively be denoted as wireless reference nodes 1 and 2, respectively, and either node may correspond to the wireless reference node as referenced with respect to the process  1800  of  FIG. 18 . In  FIG. 19 , target UE  1904  receives downlink signal (e.g., DL-PRS)  1912  from the base station  1902 , the first wireless reference node  1906  receives RS-P  1914  (e.g., DL-PRS, a new PRS type, etc.) from the base station  1902 , the second wireless reference node  1908  receives RS-P  1916  (e.g., DL-PRS, a new PRS type, etc.) from the base station  1902 , and target UE  1910  receives downlink signal (e.g., DL-PRS)  1918  from the base station  1902 . The target UE  1904 , the first wireless reference node  1906 , the second wireless reference node  1908  and the target UE  1910  each measure AoD (or RSRP, which may in turn be used to estimate AoD with knowledge of beam pattern) with respect to the above-noted RS-Ps  1912 - 1918 , respectively. In some designs, an AoD bias determined from the AoD of the RS-P  1914  may be used for calibration of the AoD of the downlink signal (e.g., DL-PRS)  1912 , and an AoD bias determined from the AoD of the RS-P  1916  may be used for calibration of the AoD of the downlink signal (e.g., DL-PRS)  1918 . In this case, the first wireless reference node  1906  may be selected for calibration of the target UE  1904  due to their alignment in terms of angle, location, frequency domain, etc., and likewise the second wireless reference node  1908  may be selected for calibration of the target UE  1910  due to their alignment in terms of angle, location, frequency domain, etc. 
       FIG. 20  illustrates an example implementation  2000  of the process  1800  of  FIG. 18  in accordance with another aspect of the disclosure.  2002 - 2018  of  FIG. 20  are similar to  1902 - 1918  of  FIG. 19 , respectively, except that the first wireless reference node  1906  and the second wireless reference node  1908  are more specifically illustrated as gNBs  2006  and  2008 , respectively, in  FIG. 20 .  FIGS. 19-20  are otherwise the same, and as such  FIG. 20  will not be discussed further for the sake of brevity. 
       FIG. 21  illustrates an example implementation  2100  of the process  1800  of  FIG. 18  in accordance with another aspect of the disclosure.  2102 - 2118  of  FIG. 21  are similar to  1902 - 1918  of  FIG. 19 , respectively, except that the first wireless reference node  1906  and the second wireless reference node  1908  are more specifically illustrated as UEs  2106  and  2108 , respectively, in  FIG. 21 .  FIGS. 19 and 21  are otherwise the same, and as such  FIG. 20  will not be discussed further for the sake of brevity. 
     In the detailed description above it can be seen that different features are grouped together in examples. This manner of disclosure should not be understood as an intention that the example clauses have more features than are explicitly mentioned in each clause. Rather, the various aspects of the disclosure may include fewer than all features of an individual example clause disclosed. Therefore, the following clauses should hereby be deemed to be incorporated in the description, wherein each clause by itself can stand as a separate example. Although each dependent clause can refer in the clauses to a specific combination with one of the other clauses, the aspect(s) of that dependent clause are not limited to the specific combination. It will be appreciated that other example clauses can also include a combination of the dependent clause aspect(s) with the subject matter of any other dependent clause or independent clause or a combination of any feature with other dependent and independent clauses. The various aspects disclosed herein expressly include these combinations, unless it is explicitly expressed or can be readily inferred that a specific combination is not intended (e.g., contradictory aspects, such as defining an element as both an insulator and a conductor). Furthermore, it is also intended that aspects of a clause can be included in any other independent clause, even if the clause is not directly dependent on the independent clause. 
     Implementation examples are described in the following numbered clauses: 
     Clause 1. A method of operating a communications device, comprising: obtaining a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtaining a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and calibrating the second AoA measurement based on the residual AoA bias. 
     Clause 2. The method of clause 1, wherein the uplink signal corresponds to a physical random access channel (PRACH) signal, or wherein the uplink signal corresponds to sounding reference signal (SRS), or wherein the uplink signal corresponds to an SRS for positioning (SRS-P), or a combination thereof. 
     Clause 3. The method of any of clauses 1 to 2, wherein the residual AoA bias is received from the first base station, or wherein the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Clause 4. The method of any of clauses 1 to 3, wherein the communications device corresponds to a position estimation entity, further comprising: determining a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Clause 5. The method of any of clauses 1 to 4, wherein the communications device corresponds to the first base station, further comprising: transmitting the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Clause 6. The method of any of clauses 1 to 5, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoA measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 7. The method of any of clauses 1 to 6, further comprising: selecting the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. 
     Clause 8. The method of clause 7, wherein the selection is based upon a lookup table. 
     Clause 9. The method of any of clauses 1 to 8, wherein the first AoA measurement comprises a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoA measurement comprises a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 10. A method of operating a communications device, comprising: obtaining a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtaining a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and calibrating the second AoD measurement based on the residual AoD bias. 
     Clause 11. The method of clause 10, wherein the downlink signal corresponds to a positioning reference signal (PRS). 
     Clause 12. The method of any of clauses 10 to 11, wherein the residual AoD bias is received from the first base station or the wireless reference node, or wherein the first AoD measurement is received from the first base station or the wireless reference node, and the residual AoD bias is derived at the communications device based on the first AoD measurement, or wherein reference signal received power (RSRP) measurements and beam pattern information are received from the first base station or the wireless reference node for derivation of the first AoD measurement. 
     Clause 13. The method of any of clauses 10 to 12, wherein the calibrating is performed in association with UE-based position estimation of the UE. 
     Clause 14. The method of clause 13, wherein the communications device corresponds to the wireless reference node, further comprising: transmitting, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or reference signal received power (RSRP) measurements of the RS-P, or receiving a beam pattern of the RS-P from which the first AoD measurement is derivable. 
     Clause 15. The method of any of clauses 13 to 14, wherein the communications device corresponds to the UE, further comprising: receiving reference signal received power (RSRP) measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or receiving the first AoD measurement, or receiving the residual AoD bias. 
     Clause 16. The method of clause 15, wherein the residual AoD bias is received from a location management function (LMF). 
     Clause 17. The method of any of clauses 10 to 16, wherein the communications device corresponds to a position estimation entity, further comprising: determining a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Clause 18. The method of any of clauses 10 to 17, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoD measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 19. The method of any of clauses 10 to 18, further comprising: selecting the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location or a combination thereof. 
     Clause 20. The method of clause 19, wherein the selection is based upon a lookup table. 
     Clause 21. The method of clause 20, wherein the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 22. The method of any of clauses 10 to 21, wherein the wireless reference node corresponds to a second base station, further comprising: receiving, from the second base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. 
     Clause 23. A communications device, comprising: 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 residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtain a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and calibrate the second AoA measurement based on the residual AoA bias. 
     Clause 24. The communications device of clause 23, wherein the uplink signal corresponds to a physical random access channel (PRACH) signal, or wherein the uplink signal corresponds to sounding reference signal (SRS), or wherein the uplink signal corresponds to an SRS for positioning (SRS-P), or a combination thereof. 
     Clause 25. The communications device of any of clauses 23 to 24, wherein the residual AoA bias is received from the first base station, or wherein the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Clause 26. The communications device of any of clauses 23 to 25, wherein the communications device corresponds to a position estimation entity, further comprising: determine a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Clause 27. The communications device of any of clauses 23 to 26, wherein the communications device corresponds to the first base station, further comprising: transmit, via the at least one transceiver, the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Clause 28. The communications device of any of clauses 23 to 27, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoA measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 29. The communications device of any of clauses 23 to 28, wherein the at least one processor is further configured to: select the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. 
     Clause 30. The communications device of clause 29, wherein the selection is based upon a lookup table. 
     Clause 31. The communications device of any of clauses 23 to 30, wherein the first AoA measurement comprises a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoA measurement comprises a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 32. A communications device, comprising: 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 residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtain a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and calibrate the second AoD measurement based on the residual AoD bias. 
     Clause 33. The communications device of clause 32, wherein the downlink signal corresponds to a positioning reference signal (PRS). 
     Clause 34. The communications device of any of clauses 32 to 33, wherein the residual AoD bias is received from the first base station or the wireless reference node, or wherein the first AoD measurement is received from the first base station or the wireless reference node, and the residual AoD bias is derived at the communications device based on the first AoD measurement, or wherein reference signal received power (RSRP) measurements and beam pattern information are received from the first base station or the wireless reference node for derivation of the first AoD measurement. 
     Clause 35. The communications device of any of clauses 32 to 34, wherein the calibrating is performed in association with UE-based position estimation of the UE. 
     Clause 36. The communications device of clause 35, wherein the communications device corresponds to the wireless reference node, further comprising: transmit, via the at least one transceiver, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or reference signal received power (RSRP) measurements of the RS-P, or receive, via the at least one transceiver, a beam pattern of the RS-P from which the first AoD measurement is derivable. 
     Clause 37. The communications device of any of clauses 35 to 36, wherein the communications device corresponds to the UE, further comprising: receive, via the at least one transceiver, reference signal received power (RSRP) measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or receive, via the at least one transceiver, the first AoD measurement, or receive, via the at least one transceiver, the residual AoD bias. 
     Clause 38. The communications device of clause 37, wherein the residual AoD bias is received from a location management function (LMF). 
     Clause 39. The communications device of any of clauses 32 to 38, wherein the communications device corresponds to a position estimation entity, further comprising: determine a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Clause 40. The communications device of any of clauses 32 to 39, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoD measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 41. The communications device of any of clauses 32 to 40, wherein the at least one processor is further configured to: select the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location or a combination thereof. 
     Clause 42. The communications device of clause 41, wherein the selection is based upon a lookup table. 
     Clause 43. The communications device of clause 42, wherein the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 44. The communications device of any of clauses 32 to 43, wherein the wireless reference node corresponds to a second base station, further comprising: receive, via the at least one transceiver, from the second base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. 
     Clause 45. A communications device, comprising: means for obtaining a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; means for obtaining a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and means for calibrating the second AoA measurement based on the residual AoA bias. 
     Clause 46. The communications device of clause 45, wherein the uplink signal corresponds to a physical random access channel (PRACH) signal, or wherein the uplink signal corresponds to sounding reference signal (SRS), or wherein the uplink signal corresponds to an SRS for positioning (SRS-P), or a combination thereof. 
     Clause 47. The communications device of any of clauses 45 to 46, wherein the residual AoA bias is received from the first base station, or wherein the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Clause 48. The communications device of any of clauses 45 to 47, wherein the communications device corresponds to a position estimation entity, further comprising: means for determining a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Clause 49. The communications device of any of clauses 45 to 48, wherein the communications device corresponds to the first base station, further comprising: means for transmitting the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Clause 50. The communications device of any of clauses 45 to 49, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoA measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 51. The communications device of any of clauses 45 to 50, further comprising: means for selecting the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. 
     Clause 52. The communications device of clause 51, wherein the selection is based upon a lookup table. 
     Clause 53. The communications device of any of clauses 45 to 52, wherein the first AoA measurement comprises a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoA measurement comprises a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 54. A communications device, comprising: means for obtaining a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; means for obtaining a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and means for calibrating the second AoD measurement based on the residual AoD bias. 
     Clause 55. The communications device of clause 54, wherein the downlink signal corresponds to a positioning reference signal (PRS). 
     Clause 56. The communications device of any of clauses 54 to 55, wherein the residual AoD bias is received from the first base station or the wireless reference node, or wherein the first AoD measurement is received from the first base station or the wireless reference node, and the residual AoD bias is derived at the communications device based on the first AoD measurement, or wherein reference signal received power (RSRP) measurements and beam pattern information are received from the first base station or the wireless reference node for derivation of the first AoD measurement. 
     Clause 57. The communications device of any of clauses 54 to 56, wherein the calibrating is performed in association with UE-based position estimation of the UE. 
     Clause 58. The communications device of clause 57, wherein the communications device corresponds to the wireless reference node, further comprising: means for transmitting, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or reference signal received power (RSRP) measurements of the RS-P, or means for receiving a beam pattern of the RS-P from which the first AoD measurement is derivable. 
     Clause 59. The communications device of any of clauses 57 to 58, wherein the communications device corresponds to the UE, further comprising: means for receiving reference signal received power (RSRP) measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or means for receiving the first AoD measurement, or means for receiving the residual AoD bias. 
     Clause 60. The communications device of clause 59, wherein the residual AoD bias is received from a location management function (LMF). 
     Clause 61. The communications device of any of clauses 54 to 60, wherein the communications device corresponds to a position estimation entity, further comprising: means for determining a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Clause 62. The communications device of any of clauses 54 to 61, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoD measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 63. The communications device of any of clauses 54 to 62, further comprising: means for selecting the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location or a combination thereof. 
     Clause 64. The communications device of clause 63, wherein the selection is based upon a lookup table. 
     Clause 65. The communications device of clause 64, wherein the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 66. The communications device of any of clauses 54 to 65, wherein the wireless reference node corresponds to a second base station, further comprising: means for receiving, from the second base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. 
     Clause 67. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a communications device, cause the communications device to: obtain a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtain a second angle of arrival (AoA) measurement associated with an uplink signal transmitted from a user equipment (UE) to the first base station; and calibrate the second AoA measurement based on the residual AoA bias. 
     Clause 68. The non-transitory computer-readable medium of clause 67, wherein the uplink signal corresponds to a physical random access channel (PRACH) signal, or wherein the uplink signal corresponds to sounding reference signal (SRS), or wherein the uplink signal corresponds to an SRS for positioning (SRS-P), or a combination thereof. 
     Clause 69. The non-transitory computer-readable medium of any of clauses 67 to 68, wherein the residual AoA bias is received from the first base station, or wherein the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Clause 70. The non-transitory computer-readable medium of any of clauses 67 to 69, wherein the communications device corresponds to a position estimation entity, further comprising: determine a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Clause 71. The non-transitory computer-readable medium of any of clauses 67 to 70, wherein the communications device corresponds to the first base station, further comprising: transmit the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Clause 72. The non-transitory computer-readable medium of any of clauses 67 to 71, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoA measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 73. The non-transitory computer-readable medium of any of clauses 67 to 72, further comprising computer-executable instructions that, when executed by the communications device, cause the communications device to: select the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. 
     Clause 74. The non-transitory computer-readable medium of clause 73, wherein the selection is based upon a lookup table. 
     Clause 75. The non-transitory computer-readable medium of any of clauses 67 to 74, wherein the first AoA measurement comprises a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoA measurement comprises a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 76. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a communications device, cause the communications device to: obtain a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtain a second AoD measurement associated with a downlink signal transmitted from the first base station to a user equipment (UE); and calibrate the second AoD measurement based on the residual AoD bias. 
     Clause 77. The non-transitory computer-readable medium of clause 76, wherein the downlink signal corresponds to a positioning reference signal (PRS). 
     Clause 78. The non-transitory computer-readable medium of any of clauses 76 to 77, wherein the residual AoD bias is received from the first base station or the wireless reference node, or wherein the first AoD measurement is received from the first base station or the wireless reference node, and the residual AoD bias is derived at the communications device based on the first AoD measurement, or wherein reference signal received power (RSRP) measurements and beam pattern information are received from the first base station or the wireless reference node for derivation of the first AoD measurement. 
     Clause 79. The non-transitory computer-readable medium of any of clauses 76 to 78, wherein the calibrating is performed in association with UE-based position estimation of the UE. 
     Clause 80. The non-transitory computer-readable medium of clause 79, wherein the communications device corresponds to the wireless reference node, further comprising: transmit, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or reference signal received power (RSRP) measurements of the RS-P, or receive a beam pattern of the RS-P from which the first AoD measurement is derivable. 
     Clause 81. The non-transitory computer-readable medium of any of clauses 79 to 80, wherein the communications device corresponds to the UE, further comprising: receive reference signal received power (RSRP) measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or receive the first AoD measurement, or receive the residual AoD bias. 
     Clause 82. The non-transitory computer-readable medium of clause 81, wherein the residual AoD bias is received from a location management function (LMF). 
     Clause 83. The non-transitory computer-readable medium of any of clauses 76 to 82, wherein the communications device corresponds to a position estimation entity, further comprising: determine a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Clause 84. The non-transitory computer-readable medium of any of clauses 76 to 83, wherein the wireless reference node corresponds to a second base station or a reference UE, or wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS, or wherein the first AoD measurement is triggered periodically, aperiodically, or on-demand, or any combination thereof. 
     Clause 85. The non-transitory computer-readable medium of any of clauses 76 to 84, further comprising computer-executable instructions that, when executed by the communications device, cause the communications device to: select the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location or a combination thereof. 
     Clause 86. The non-transitory computer-readable medium of clause 85, wherein the selection is based upon a lookup table. 
     Clause 87. The non-transitory computer-readable medium of clause 86, wherein the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof 
     Clause 88. The non-transitory computer-readable medium of any of clauses 76 to 87, wherein the wireless reference node corresponds to a second base station, further comprising: receive, from the second base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. 
     Additional implementation examples are described in the following numbered clauses: 
     Clause 1. A method of operating a communications device, comprising: obtaining a residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtaining a second angle of arrival (AoA) measurement associated with an uplink sounding reference signal for positioning (UL-SRS-P) transmitted from a user equipment (UE) to the first base station; and calibrating the second AoA measurement based on the residual AoA bias. 
     Clause 2. The method of clause 1, wherein the residual AoA bias is received from the first base station, or wherein the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Clause 3. The method of any of clauses 1 to 2, wherein the communications device corresponds to a position estimation entity, further comprising: determining a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Clause 4. The method of any of clauses 1 to 3, wherein the communications device corresponds to the first base station, further comprising: transmitting the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Clause 5. The method of any of clauses 1 to 4, wherein the wireless reference node corresponds to a second base station or a reference UE. 
     Clause 6. The method of any of clauses 1 to 5, wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS. 
     Clause 7. The method of any of clauses 1 to 6, wherein the first AoA measurement is triggered periodically, aperiodically, or on-demand. 
     Clause 8. The method of any of clauses 1 to 7, further comprising: selecting the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. 
     Clause 9. The method of any of clauses 1 to 8, wherein the first AoA measurement comprises a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoA measurement comprises a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 10. A method of operating a communications device, comprising: obtaining a residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtaining a second AoD measurement associated with a downlink positioning reference signal (DL-PRS) transmitted from the first base station to a user equipment (UE); and calibrating the second AoD measurement based on the residual AoD bias. 
     Clause 11. The method of any of clauses 11 to 10, wherein the residual AoD bias is received from the first base station or the wireless reference node, or wherein the first AoD measurement is received from the first base station or the wireless reference node, and the residual AoD bias is derived at the communications device based on the first AoD measurement, or wherein reference signal received power (RSRP) measurements and beam pattern information are received from the first base station or the wireless reference node for derivation of the first AoD measurement. 
     Clause 12. The method of clause 11, wherein the calibrating is performed in association with UE-based position estimation of the UE. 
     Clause 13. The method of any of clauses 13 to 12, wherein the communications device corresponds to the wireless reference node, further comprising: transmitting, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or reference signal received power (RSRP) measurements of the RS-P, or receiving a beam pattern of the RS-P from which the first AoD measurement is derivable. 
     Clause 14. The method of clause 13, wherein the communications device corresponds to the UE, further comprising: receiving reference signal received power (RSRP) measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or receiving the first AoD measurement, or receiving the residual AoD bias. 
     Clause 15. The method of any of clauses 15 to 14, wherein the residual AoD bias is received from a location management function (LMF). 
     Clause 16. The method of any of clauses 10 to 15, wherein the communications device corresponds to a position estimation entity, further comprising: determining a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Clause 17. The method of any of clauses 10 to 16, wherein the wireless reference node corresponds to a second base station or a reference UE. 
     Clause 18. The method of any of clauses 10 to 17, wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS. 
     Clause 19. The method of any of clauses 10 to 18, wherein the first AoD measurement is triggered periodically, aperiodically, or on-demand. 
     Clause 20. The method of any of clauses 10 to 19, further comprising: selecting the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location or a combination thereof. 
     Clause 21. The method of any of clauses 10 to 20, wherein the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 22. The method of any of clauses 10 to 21, wherein the wireless reference node corresponds to a second base station, further comprising: receiving, from the second base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. 
     Clause 23. A communications device, comprising: 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 residual angle of arrival (AoA) bias associated with a first AoA measurement of a reference signal for positioning (RS-P) transmitted from a wireless reference node to a first base station, the wireless reference node associated with a location known to the communications device; obtain a second angle of arrival (AoA) measurement associated with an uplink sounding reference signal for positioning (UL-SRS-P) transmitted from a user equipment (UE) to the first base station; and calibrate the second AoA measurement based on the residual AoA bias. 
     Clause 24. The communications device of any of clauses 24 to 23, wherein the residual AoA bias is received from the first base station, or wherein the first AoA measurement is received from the first base station, and the residual AoA bias is derived at the communications device based on the first AoA measurement. 
     Clause 25. The communications device of any of clauses 1 to 24, wherein the communications device corresponds to a position estimation entity, further comprising: determine a positioning estimate of the UE based on the calibrated second AoA measurement. 
     Clause 26. The communications device of any of clauses 24 to 25, wherein the communications device corresponds to the first base station, further comprising: transmit the calibrated second AoA measurement to a position estimation entity for position estimation of the UE. 
     Clause 27. The communications device of any of clauses 24 to 26, wherein the wireless reference node corresponds to a second base station or a reference UE. 
     Clause 28. The communications device of any of clauses 24 to 27, wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS. 
     Clause 29. The communications device of any of clauses 24 to 28, wherein the first AoA measurement is triggered periodically, aperiodically, or on-demand. 
     Clause 30. The communications device of any of clauses 24 to 29, wherein the at least one processor is further configured to: select the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location, or a combination thereof. 
     Clause 31. The communications device of any of clauses 24 to 30, wherein the first AoA measurement comprises a first respective time stamp, a first respective absolute AoA, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoA measurement comprises a second respective time stamp, a second respective absolute AoA, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 32. A communications device, comprising: 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 residual angle of departure (AoD) bias associated with a first AoD measurement of a reference signal for positioning (RS-P) transmitted from a first base station to a wireless reference node with a known location; obtain a second AoD measurement associated with a downlink positioning reference signal (DL-PRS) transmitted from the first base station to a user equipment (UE); and calibrate the second AoD measurement based on the residual AoD bias. 
     Clause 33. The communications device of any of clauses 34 to 32, wherein the residual AoD bias is received from the first base station or the wireless reference node, or wherein the first AoD measurement is received from the first base station or the wireless reference node, and the residual AoD bias is derived at the communications device based on the first AoD measurement, or wherein reference signal received power (RSRP) measurements and beam pattern information are received from the first base station or the wireless reference node for derivation of the first AoD measurement. 
     Clause 34. The communications device of any of clauses 34 to 33, wherein the calibrating is performed in association with UE-based position estimation of the UE. 
     Clause 35. The communications device of any of clauses 36 to 34, wherein the communications device corresponds to the wireless reference node, further comprising: transmit, to a location management function (LMF), the residual AoD bias, the first AoD measurement, or reference signal received power (RSRP) measurements of the RS-P, or receive a beam pattern of the RS-P from which the first AoD measurement is derivable. 
     Clause 36. The communications device of any of clauses 36 to 35, wherein the communications device corresponds to the UE, further comprising: receive reference signal received power (RSRP) measurements and a beam pattern of the RS-P from which the first AoD measurement is derivable, or receive the first AoD measurement, or receive the residual AoD bias. 
     Clause 37. The communications device of any of clauses 35 to 36, wherein the residual AoD bias is received from a location management function (LMF). 
     Clause 38. The communications device of any of clauses 34 to 37, wherein the communications device corresponds to a position estimation entity, further comprising: determine a positioning estimate of the UE based on the calibrated second AoD measurement. 
     Clause 39. The communications device of any of clauses 34 to 38, wherein the wireless reference node corresponds to a second base station or a reference UE. 
     Clause 40. The communications device of any of clauses 34 to 39, wherein the RS-P corresponds to a single symbol positioning reference signal (PRS) or a multi-symbol PRS. 
     Clause 41. The communications device of any of clauses 34 to 40, wherein the first AoD measurement is triggered periodically, aperiodically, or on-demand. 
     Clause 42. The communications device of any of clauses 34 to 41, wherein the at least one processor is further configured to: select the wireless reference node from among a plurality of wireless reference nodes based on the wireless reference node and the UE being aligned in terms of angle domain, frequency domain, carrier frequency, location or a combination thereof. 
     Clause 43. The communications device of any of clauses 34 to 42, wherein the first AoD measurement is obtained in association with a first respective time stamp, a first respective absolute AoD, an identifier of the wireless reference node, and an identifier of the first base station, or wherein the second AoD measurement is obtained in association with a second respective time stamp, a second respective absolute AoD, an identifier of the UE, and the identifier of the first base station, or a combination thereof. 
     Clause 44. The communications device of any of clauses 34 to 43, wherein the wireless reference node corresponds to a second base station, further comprising: receive, from the second base station, a capability indication that indicates that the second base station is capable of performing digital receive (Rx) beamforming-based AoD estimation. 
     Clause 45. An apparatus comprising a memory, a transceiver, and a processor communicatively coupled to the memory and the transceiver, the memory, the transceiver, and the processor configured to perform a method according to any of clauses 1 to 44. 
     Clause 46. An apparatus comprising means for performing a method according to any of clauses 1 to 44. 
     Clause 47. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable comprising at least one instruction for causing a computer or processor to perform a method according to any of clauses 1 to 44. 
     Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     Further, those of skill 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. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. 
     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. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. 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 any other such configuration. 
     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. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). In the alternative, the processor and the storage medium may reside as discrete components in a user terminal. 
     In one or more exemplary aspects, the functions described 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 computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of 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. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (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 medium. 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. Combinations of the above should also be included within the scope of computer-readable media. 
     While the foregoing disclosure shows illustrative aspects of the disclosure, it should be noted that various changes and modifications could be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.