Patent Publication Number: US-2022239436-A1

Title: Signaling of reception-to-transmission measurements for round-trip-time (rtt)-based positioning

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present Application for Patent is a continuation of U.S. patent application Ser. No. 16/739,054, entitled “SIGNALING OF RECEPTION-TO-TRANSMISSION MEASUREMENTS FOR ROUND-TRIP-TIME (RTT)-BASED POSITIONING,” filed Jan. 9, 2020, which claims priority to Greek Patent Application No. 20190100017, entitled “MEASUREMENT SIGNALING OF RX-TX FROM GNBS AND UES FOR RTT-BASED POSITIONING,” filed Jan. 11, 2019, each of which is assigned to the assignee hereof, and expressly incorporated herein by reference in its entirety. 
    
    
     INTRODUCTION 
     1. Technical Field 
     Various aspects described herein generally relate to wireless communication systems, and more particularly, to measurement signaling of Rx-Tx from gNodeBs (gNBs) and user equipments (UEs) for round trip time (RTT) based positioning in wireless networks, e.g., in new radio (NR). 
     2. Background 
     Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks), a third-generation (3G) high speed data, Internet-capable wireless service and a fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax). There are presently many different types of wireless communication systems in use, including cellular and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog advanced mobile phone system (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, etc. 
     A fifth generation (5G) mobile standard, referred to as New Radio (NR), calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with 1 gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards. 
     Some wireless communication networks, such as 5G, support operation at very high and even extremely-high frequency (EHF) bands, such as millimeter wave (mmW) frequency bands (generally, wavelengths of 1 mm to 10 mm, or 30 to 300 GHz). These extremely high frequencies may support very high throughput such as up to six gigabits per second (Gbps). 
     To support position estimations in terrestrial wireless networks, a mobile device can be configured to measure and report the observed time difference of arrival (OTDOA) or reference signal timing difference (RSTD) between reference RF signals received from two or more network nodes (e.g., different base stations or different transmission points (e.g., antennas) belonging to the same base station). The mobile device can also be configured to report the time of arrival (ToA) of RF signals. 
     With OTDOA, when the mobile device reports the time difference of arrival (TDOA) between RF signals from two network nodes, the location of the mobile device is then known to lie on a hyperbola with the locations of the two network nodes as the foci. Measuring TDOAs between multiple pairs of network nodes allows for solving for the mobile device&#39;s position as intersections of the hyperbolas. 
     Round trip time (RTT) is another technique for determining a position of a mobile device. RTT is a technique using both the mobile device and the network node receive-to-transmit (Rx-Tx) time differences to compute the mobile device&#39;s position. This allows for computing the back-and-forth flight time between the mobile device and the network node. The location of the mobile device is then known to lie on a circle with a center at the network node&#39;s position. Reporting RTTs with multiple network nodes allows the positioning entity to solve for the mobile device&#39;s position as the intersections of the circles. 
     SUMMARY 
     This summary identifies features of some example aspects, and is not an exclusive or exhaustive description of the disclosed subject matter. Whether features or aspects are included in, or omitted from this summary is not intended as indicative of relative importance of such features. Additional features and aspects are described, and will become apparent to persons skilled in the art upon reading the following detailed description and viewing the drawings that form a part thereof. 
     An exemplary method performed by a positioning entity is disclosed. The method comprises gathering a plurality of transmission-reception point (TRP) round trip time (RTT) related measurements, the plurality of TRP RTT-related measurements being one-to-one associated with a plurality of TRPs, wherein each TRP RTT-related measurement is associated with one TRP of the plurality of TRPs. The method also comprises gathering a plurality of user equipment (UE) RTT-related measurements, wherein each of the plurality of UE RTT-related measurements is associated with one TRP of the plurality of TRPs. The method further comprises determining a position of a UE based on the plurality of TRP RTT-related measurements and the plurality of UE RTT-related measurements. For each TRP of the plurality of TRPs, the TRP RTT-related measurement associated with that TRP represents a duration between that TRP transmitting a downlink reference signal (DL RS) to the UE and that TRP receiving a corresponding uplink reference signal (UL RS) from the UE. Also for each TRP, the UE RTT-related measurement associated with that TRP represents a duration between the UE receiving the DL RS from that TRP and the UE transmitting the corresponding UL RS to that TRP. 
     An exemplary positioning entity is disclosed. A positioning entity may be a UE or a TRP or a location server or other network entity or some combination thereof. The positioning entity may comprise a transceiver (e.g., when the positioning entity is a UE or TRP) or a network interface (e.g., when the positioning entity is a location server or other network entity) or a combination thereof (e.g., when the positioning entity is a TRP), a memory, and at least one processor. The at least one processor is configured to gather a plurality of TRP RTT-related measurements, the plurality of TRP RTT-related measurements being one-to-one associated with a plurality of TRPs, wherein each TRP RTT-related measurement is associated with one TRP of the plurality of TRPs. The at least one processor is also configured to gather a plurality of UE RTT-related measurements, wherein each of the plurality of UE RTT-related measurements is associated with one TRP of the plurality of TRPs. The at least one processor is further configured to determine a position of a UE based on the plurality of TRP RTT-related measurements and the plurality of UE RTT-related measurements. For each TRP of the plurality of TRPs, the TRP RTT-related measurement associated with that TRP represents a duration between that TRP transmitting a DL RS to the UE and that TRP receiving a corresponding UL RS from the UE. Also for each TRP, the UE RTT-related measurement associated with that TRP represents a duration between the UE receiving the DL RS from that TRP and the UE transmitting the corresponding UL RS to that TRP. 
     Another exemplary positioning entity is disclosed. The positioning entity comprises means for gathering a plurality of TRP RTT-related measurements, the plurality of TRP RTT-related measurements being one-to-one associated with a plurality of TRPs, wherein each TRP RTT-related measurement is associated with one TRP of the plurality of TRPs. The positioning entity also comprises means for gathering a plurality of UE RTT-related measurements, wherein each of the plurality of UE RTT-related measurements is associated with one TRP of the plurality of TRPs. The positioning entity further comprises means for determining a position of a UE based on the plurality of TRP RTT-related measurements and the plurality of UE RTT-related measurements. For each TRP of the plurality of TRPs, the TRP RTT-related measurement associated with that TRP represents a duration between that TRP transmitting a DL RS to the UE and that TRP receiving a corresponding UL RS from the UE. Also for each TRP, the UE RTT-related measurement associated with that TRP represents a duration between the UE receiving the DL RS from that TRP and the UE transmitting the corresponding UL RS to that TRP. 
     An exemplary non-transitory computer-readable medium storing computer-executable instructions for a positioning entity is disclosed. The computer-executable instructions comprise one or more instructions causing the positioning entity to gather a plurality of TRP RTT-related measurements, the plurality of TRP RTT-related measurements being one-to-one associated with a plurality of TRPs, wherein each TRP RTT-related measurement is associated with one TRP of the plurality of TRPs. The computer-executable instructions also comprise one or more instructions causing the positioning entity to gather a plurality of UE RTT-related measurements, wherein each of the plurality of UE RTT-related measurements is associated with one TRP of the plurality of TRPs. The computer-executable instructions further comprise one or more instructions causing the positioning entity to determine a position of a UE based on the plurality of TRP RTT-related measurements and the plurality of UE RTT-related measurements. For each TRP of the plurality of TRPs, the TRP RTT-related measurement associated with that TRP represents a duration between that TRP transmitting a DL RS to the UE and that TRP receiving a corresponding UL RS from the UE. Also for each TRP, the UE RTT-related measurement associated with that TRP represents a duration between the UE receiving the DL RS from that TRP and the UE transmitting the corresponding UL RS to that TRP. 
     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 examples of one or more aspects of the disclosed subject matter and are provided solely for illustration of the examples and not limitation thereof: 
         FIG. 1  illustrates an exemplary wireless communications system in accordance with one or more aspects of the disclosure; 
         FIGS. 2A and 2B  illustrate example wireless network structures in accordance with one or more aspects of the disclosure; 
         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 in accordance with one or more aspects of the disclosure; 
         FIG. 4  illustrates a scenario for determining a position of a UE through a multi-RTT procedure in accordance with one or more aspects of the disclosure; 
         FIG. 5  illustrates a diagram of exemplary timings for determining an RTT between a cell and a UE in accordance with one or more aspects of the disclosure; 
         FIG. 6  illustrates a diagram of a conventional E-CID (enhanced cell ID) procedure to determine a position of a UE; 
         FIGS. 7A, 7B, and 7C  illustrate example flows of RTT measurement messages for UE-based multi-RTT positioning in accordance with an aspect of the disclosure; 
         FIGS. 8A and 8B  illustrate example flows of RTT measurement messages for UE-assisted multi-RTT positioning in which a location server (LCS) resides in a serving cell in accordance with an aspect of the disclosure; 
         FIGS. 9A, 9B, 9C, and 9D  illustrate example flows of RTT measurement messages for UE-assisted multi-RTT positioning in which an LCS is outside of serving cells in accordance with an aspect of the disclosure; 
         FIG. 10  illustrates an exemplary method performed by a positioning entity to determine a UE position in accordance with an aspect of the disclosure; 
         FIG. 11  illustrates an exemplary process performed by a UE when the UE is the positioning entity in accordance with an aspect of the disclosure; 
         FIG. 12  illustrates an exemplary process performed by a serving cell when the serving cell is the positioning entity in accordance with an aspect of the disclosure; 
         FIG. 13  illustrates an exemplary process performed by the positioning entity when the positioning entity is separate from the serving cells in accordance with an aspect of the disclosure; and 
         FIG. 14  illustrates a method in accordance with various aspects disclosed herein. 
         FIG. 15  illustrates an exemplary positioning entity  1500 , according to aspects 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, 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. 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 N11 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 ,  326 ,  356 ,  366 ), 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 ,  326 ,  356 ,  366 ), 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 ,  326 ,  356 ,  366 ), 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, and/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, sounding reference signals (SRS) transmissions 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, SRS configuration and reception 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, SRS configuration 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 RTT measurement components  342 ,  388 , and  398 , respectively. The RTT measurement components  342 ,  388 , and  398  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 RTT measurement components  342 ,  388 , and  398  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  398  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 FBS detection modules  342 ,  388 , and  398 , etc. 
       FIG. 4  illustrates an exemplary wireless communications system  400  according to aspects of the disclosure. In the example of  FIG. 4 , a UE  404  (which may correspond to any of the UEs described herein) is attempting to calculate an estimate of its position, or assist another entity (e.g., a base station or core network component, another UE, a location server, a third party application, etc.) to calculate an estimate of its position. The UE  404  may communicate wirelessly with a plurality of base stations  402 - 1 ,  402 - 2 , and  402 - 3  (collectively, base stations  402 , 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  400  (i.e., the base stations&#39; locations, geometry, etc.), the UE  404  may determine its position, or assist in the determination of its position, in a predefined reference coordinate system. In an aspect, the UE  404  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. 4  illustrates one UE  404  and three base stations  402 , as will be appreciated, there may be more UEs  404  and more base stations  402 . 
     To support position estimates, the base stations  402  may be configured to broadcast reference RF signals (e.g., PRS, NRS, CRS, TRS, CSI-RS, PSS, or SSS, etc.) to UEs  404  in their coverage area to enable a UE  404  to measure characteristics of such reference RF signals. For example, the UE  404  may measure the time of arrival (ToA) of specific reference RF signals (e.g., PRS, NRS, CRS, CSI-RS, etc.) transmitted by at least three different base stations  402 - 1 ,  402 - 2 , and  402 - 3  and may use the RTT positioning method to report these ToAs (and additional information) back to the serving base station  402  or another positioning entity (e.g., location server  230 , LMF  270 ). 
     In an aspect, although described as the UE  404  measuring reference RF signals from a base station  402 , the UE  404  may measure reference RF signals from one of multiple cells supported by a base station  402 . Where the UE  404  measures reference RF signals transmitted by a cell supported by a base station  402 , the at least two other reference RF signals measured by the UE  404  to perform the RTT procedure would be from cells supported by base stations  402  different from the first base station  402  and may have good or poor signal strength at the UE  404 . 
     In order to determine the position (x, y) of the UE  404 , the entity determining the position of the UE  404  needs to know the locations of the base stations  402 , which may be represented in a reference coordinate system as (x k , y k ), where k=1, 2, 3 in the example of  FIG. 4 . Where one of the base stations  402  (e.g., the serving base station) or the UE  404  determines the position of the UE  404 , the locations of the involved base stations  402  may be provided to the serving base station  402  or the UE  404  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  404  using the known network geometry. 
     Either the UE  404  or the respective base station  402  may determine the distance  410  (d k , where k=1, 2, 3) between the UE  404  and the respective base station  402 . Specifically, the distance  410 - 1  between the UE  404  and base station  402 - 1  is d 1 , the distance  410 - 2  between the UE  404  and base station  402 - 2  is d 2 , and the distance  410 - 3  between the UE  404  and base station  402 - 3  is d 3 . In an aspect, determining the RTT of signals exchanged between the UE  404  and any base station  402  can be performed and converted to a distance  410  (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  404  and the base stations  402  are the same. However, such an assumption may not be true in practice. 
     Once each distance  410  is determined, the UE  404 , a base station  402 , or the location server (e.g., location server  230 , LMF  270 ) can solve for the position (x, y) of the UE  404  by using a variety of known geometric techniques, such as, for example, trilateration. From  FIG. 4 , it can be seen that the position of the UE  404  ideally lies at the common intersection of three semicircles, each semicircle being defined by radius d k  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  404  from the location of a base station  402 ). The intersection of the two directions at or near the point (x, y) can provide another estimate of the location for the UE  404 . 
     A position estimate (e.g., for a UE  404 ) 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. 5  is an exemplary diagram  500  showing exemplary timings of RTT measurement signals exchanged between a base station  502  (e.g., any of the base stations described herein) and a UE  504  (e.g., any of the UEs described herein), according to aspects of the disclosure. In the example of  FIG. 5 , the base station  502  sends an RTT measurement signal  510  (e.g., PRS, NRS, CRS, CSI-RS, etc.) to the UE  504  at time T 1 . The RTT measurement signal  510  has some propagation delay T Prop  as it travels from the base station  502  to the UE  504 . At time T 2  (the ToA of the RTT measurement signal  510  at the UE  504 ), the UE  504  receives/measures the RTT measurement signal  510 . After some UE processing time, the UE  504  transmits an RTT response signal  520  (e.g., an SRS, UL-PRS) at time T 3 . After the propagation delay T Prop , the base station  502  receives/measures the RTT response signal  520  from the UE  504  at time T 4  (the ToA of the RTT response signal  520  at the base station  502 ). 
     In order to identify the ToA (e.g., T 2 ) of an RF signal (e.g., an RTT measurement signal  510 ) transmitted by a given network node, the receiver (e.g., UE  504 ) first jointly processes all the resource elements (REs) on the channel on which the transmitter (e.g., base station  502 ) is transmitting the RF signal, and performs an inverse Fourier transform to convert the received RF signals to the time domain. The conversion of the received RF 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 RF 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 UE  504  may chose a ToA estimate that is the earliest local maximum of the CER that is at least X decibels (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 RF signal from each transmitter in order to determine the ToA of each RF signal from the different transmitters. 
     The RTT response signal  520  may explicitly include the difference between time T 3  and time T 2  (i.e., T Rx→Tx ). Alternatively, it may be derived from the timing advance (TA), i.e., the relative UL/DL frame timing and specification location of UL reference signals. (Note that the TA is usually the RTT between the base station  502  and the UE  504 , or double the propagation time in one direction.) Using this measurement and the difference between time T 4  and time T 1  (i.e., T Tx→Rx ), the base station  502  can calculate the distance to the UE  504  as: 
     
       
         
           
             
               
                 
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     where c is the speed of light. 
     Note that the UE  504  can perform an RTT procedure with multiple base stations  502 . However, the RTT procedure does not require synchronization between these base stations  502 . 
     In conventional wireless networks (e.g., 4G LTE), an uplink enhanced cell ID (E-CID) procedure can be performed to determine the location of a UE. In this procedure, which is illustrated in  FIG. 6 , the following operations are performed: 
     At stage (1), the location server (e.g., an evolved serving mobile location center (E-SMLC)  630 ) sends an E-CID measurement initiation request to the serving gNB  602  over the LTE positioning protocol type A (LPPa) interface.
         At stage (2), the UE  604  (e.g., any of the UEs described herein) reports to the serving eNB  603  (e.g., any of the base stations described herein) the UE Rx-Tx =T UE,Rx −T UE,Tx  measurement;   Also at stage (2), the eNB  602  receives the UE Rx-Tx  measurement and adds the eNB Rx-Tx =T eNB,Rx −T eNB,Tx  measurement to derive T adv =UE Rx-Tx +eNB Rx-Tx ;   At stage (3), the eNB sends an E-CID measurement initiation response message to report the T adv  to the E-SMLC  630  to enable the E-SMLC  630  to perform the positioning (i.e., estimate the location of the UE  604 ).
 
The eNB  602  can also report the angle-of-arrival (AoA), and the location server can determine the UE&#39;s  604  position based on the T adv  and the AoA. In LTE, the UE  604  reports the UE Rx-Tx , referred to as “ue-RxTxtimediff,” only for the serving eNB  602 .
       

     However, in multi-RTT positioning, multiple RTTs are utilized to determine the position of the UE. More specifically, a plurality of RTT-related measurements between a plurality of cells (or TRPs) and a UE are provided to a positioning entity that determines the position of the UE. The positioning entity may be the UE itself or a location server (LCS) of a wireless network. The LCS may reside in a serving cell or may be a separate entity outside of the serving cell(s) (e.g., location server  230 , LMF  270 ). Also, depending on whether a coordinated multipoint (CoMP) (the dynamic coordination of transmission and/or reception between a UE and multiple geographically separated sites) is in effect or not, the flow of messages (i.e., who sends what messages to whom) that need to be exchanged can be different. 
     In an aspect, the following cases are identified:
         1. UE-based multi-RTT positioning:
           1.A: A designated cell transmits measurements to the UE;
               Multiple designated cells transmit measurements for diversity gain;   
               1.B: Multiple serving cells transmit their own measurements to the UE;   
           2. UE-assisted multi-RTT positioning with a serving cell as the LCS (LCS-BS):
           2.A: Non-LCS cells transmit measurements to the LCS-BS:
               The UE transmits measurements to the LCS BS, or to another serving cell, or to both for diversity gain;   
               
           3. UE-assisted multi-RTT positioning with the LCS outside of a serving cell:
           3.A: Non-designated cells transmit measurements to a designated cell, the designated cell forwards measurements to the LCS:
               The UE transmits measurements to the designated cell, or to another serving cell, or to both for diversity gain;   
               3.B: Cells transmit measurements to the LCS:
               The UE transmits measurements to a primary serving cell, or to another serving cell, or to both for diversity gain.   
               
               

     In one or more aspects, techniques/processes are proposed to ensure that all of the RTT-related measurements are provided to the positioning entity (whether it be the UE, a serving cell, or an external LCS). To ease the descriptions thereof, the following RTT-related measurement quantities are defined for k=1, 2, 3: 
       Δ UE   k   =T   UE,Rx   k   −T   UE,Tx   k   (2)
 
       Δ gNB   k   =T   gNB,Rx   k   −T   gNB,Tx   k   (3)
 
         T   adv   k =Δ UE   k +Δ gNB   k   (4)
 
     In equations (2), (3), and (4), k=1 corresponds to a primary serving cell (or simply “primary cell”), k=2 corresponds a secondary serving cell (or simply “secondary cell”) in cases of CoMP communication transmissions, and k=3 corresponds to a neighboring cell in which the UE is not being served with data from that cell. Note that a base station, such as a gNB, is an example of a cell. Therefore, gNBs will be used as specific examples of cells in the description. But it should be noted that the aspects are applicable to cells in general. 
     The quantities Δ UE   k  are measured by the UE. Hence, these quantities are also referred to as UE RTT-related measurements. As expressed in equation (2), the UE RTT-related measurements are negative (since transmission of the UL reference signal (RS) occurs after the reception of the DL RS). In the UE-assisted cases, these UE RTT-related measurements should ultimately reach the LCS. 
     Above, it is indicated that T UE,Rx   k , T UE,Tx   k  measurements are respectively the UE received timing of the DL RS, and the UE transmit timing of the corresponding UL RS. However, in some alternative aspects, the UE may actually measure a received timing of a downlink radio subframe i (e.g., 1 millisecond (ms) in the time domain) from cell k defined by the first detected path in time to estimate the T UE,Rx   k , measurement. Similarly, the UE may actually consider a transmit timing of an uplink radio subframe (e.g., 1 ms in the time domain) in which it did receive the DL transmission used for the T UE,Rx   k  estimation to estimate the T UE,Tx   k  quantities. Based on the timings of the radio subframes, the T UE,Rx   k , T UE,Tx   k  measurements may be derived/estimated. For example, knowledge of how DL RS and UL RS are configured within the subframe can be used to derive the T UE,Rx   k , T UE,Tx   k  measurements. 
     The quantities Δ gNB   k  are measured by the gNBs. Hence, these quantities are also referred to as cell RTT-related measurements. In the UE-based cases, these cell RTT-related measurements should ultimately reach the UE. In the UE-assisted cases in which the LCS is outside of the serving cell(s), these cell RTT-related measurements should ultimately reach the LCS. In the UE-assisted cases in which the LCS resides in a serving gNB, each gNB that is not the serving gNB should provide its cell RTT-related measurement to the serving gNB. 
     Above, it is indicated that T gNB,Rx   k , T gNB,Tx   k  measurements are respectively the gNB received timing of the UL RS, and the gNB transmit timing of the corresponding DL RS. However, in some alternative aspects, the cell k may actually measure a received timing of an uplink radio subframe i from the UE defined by the first detected path in time to estimate the T gNB,Rx   k  measurement. Similarly, the cell k may actually measure a transmit timing of the downlink radio subframe i. Thus, the Δ gNB   k  quantity can represent a duration between a received time of the uplink subframe i from the UE and a transmit timing of the corresponding downlink subframe. Based on the timings of the radio subframes, the T gNB,Rx   k , T gNB,Tx   k  measurements may be derived/estimated. For example, knowledge of how DL RS and UL RS are configured within the subframe can be used to derive the T gNB,Rx   k , T gNB,Tx   k  measurements. 
     The quantities T adv   k  are determined by the positioning entity based on the UE and the cell RTT-related measurements. Note that the quantity T adv   k  is equal to the RTT between a gNB k and the UE. From the multiple RTTs and with the knowledge of the locations of the gNBs, the positioning entity (be it the UE, the serving gNB, or the external LCS) determines the position of the UE. 
       FIGS. 7A, 7B, and 7C  illustrate example flows of RTT measurement messages for UE-based multi-RTT positioning among a UE  710  (e.g., any of the UEs described herein), a primary gNB  720  (k=1), a secondary gNB  730  (k=2), and a neighboring gNB  740  (k=3). While one secondary gNB  730  is shown in each of  FIGS. 7A, 7B, and 7C , there can be any number, i.e., zero or more, of secondary gNBs  730 . Also, while one neighboring gNB  740  is shown, there can be any number, i.e., zero or more, of neighboring gNBs  740 . It is nonetheless assumed that there is a plurality of gNBs. 
     In these figures, the primary gNB  720  determines its quantity Δ gNB   1 , each secondary gNB  730  determines its corresponding quantity Δ gNB   2 , and each neighboring gNB  740  determines its corresponding quantity Δ gNB   3 . The UE  710  determines the quantity Δ UE   1  associated with the primary gNB  720 , determines the quantity D UE  associated with each secondary gNB  730 , and determines the quantity Δ UE   3  associated with each neighboring gNB  740 . 
     In  FIGS. 7A and 7B , a designated gNB transmits the necessary cell RTT-related measurements to the UE  710 . The designated gNB can be any of the serving gNBs—the primary gNB  720  or any of the secondary gNBs  730 . The designated gNB is the gNB that has a communication connection with the UE  710 . In scenarios in which there is no non-coherent CoMP, the primary gNB  730  can be the designated gNB. On the other hand, in scenarios in which there is a non-coherent CoMP, a serving gNB (the primary gNB  720  or the secondary gNB  730 ) with the highest link quality can be chosen as the designated gNB. The link quality may be determined based on a CSF (channel state feedback) report and/or based on a RSRP and/or reference signal received quality (RSRQ) report. 
     The designated gNB gathers the measurements from other gNBs, and forwards them to the UE  710 . In this specification, “gathering” is intended to indicate that the information (e.g., measurements) are generated directly by an entity (e.g., gNB, UE, location server) or are received from other entities. In  FIG. 7A , the primary gNB  720  is assumed to be the designated gNB (e.g., non-coherent CoMP is not in effect or the primary gNB  720  has the highest link quality). All other gNBs send their measurement quantities to the primary gNB  720 . That is, each secondary gNB  730  sends its Δ gNB   2  quantity to the primary gNB  720 , and each neighboring gNB  740  sends its Δ gNB   3  quantity to the primary gNB  720 . The primary gNB  720  sends its own Δ gNB   1  quantity along with the gathered Δ gNB   2 , Δ gNB   3  quantities to the UE  710 . For example, a physical downlink shared channel (PDSCH) and/or a physical downlink control channel (PDCCH) may be utilized to transmit the quantities to the UE  710 . 
     In  FIG. 7B , the secondary gNB  730  is assumed to be the designated gNB (e.g., non-coherent CoMP is in effect and the secondary gNB  730  has the highest link quality). All other gNBs send their measurement quantities to the secondary gNB  730 . That is, the primary gNB  720  sends its Δ gNB   1  quantity to the designated secondary gNB  730 , each of the other secondary gNBs  730  sends its Δ gNB   2  quantity to the designated secondary gNB  730 , and each neighboring gNB  740  sends its Δ gNB   3  quantity to the designated secondary gNB  730 . The designated secondary gNB  730  sends its own Δ gNB   2  quantity along with the gathered Δ gNB   1 , Δ gNB   2 , Δ gNB   3  quantities to the UE  710 . Again, the PDSCH and/or PDCCH may be utilized to transmit the quantities to the UE  710 . 
     In an aspect, the designated gNB can be switched dynamically. For example, in one instance, the primary gNB  720  can gather and send the measurement quantities to the UE  710  to determine its location. In the next instance of when the UE  710  determines its position, the secondary gNB  730  can gather and send the measurement quantities. 
     In  FIGS. 7A and 7B , one designated gNB (the primary gNB  720  or the secondary gNB  730 ) is illustrated as sending the measurement quantities to the UE  710 . However, while not specifically shown, multiple serving gNBs (any combination of the primary gNB  720  and/or the secondary gNBs  730  (recall that there can be any number of the secondary gNBs  730 )) may send the gathered measurement quantities to the UE  710  for diversity gain. 
     In  FIG. 7C , each serving gNB sends its RTT-related measurement directly to the UE  710 . That is, the primary gNB  720  sends its Δ gNB   1  quantity to the UE  710 , and each secondary gNB  730  sends its Δ gNB   2  quantity to the UE  710 . However, since the neighboring gNB  740  is not in data communication with the UE  710 , each neighboring gNB  740  sends its Δ gNB   3  quantity to a serving gNBs (the primary gNB  720  or the secondary gNB  730 ), which in turn forwards the received quantity to the UE  710 . Yet again, the PDSCH and/or PDCCH may be utilized. 
     In  FIGS. 7A, 7B, and 7C , since the UE  710  receives the cell RTT-related measurements (quantities Δ gNB   1 , Δ gNB   2 , Δ gNB   3 ) and is in possession of the UE RTT-related measurements (quantities Δ UE   1 , Δ UE   2 , Δ UE   3 ) through measurements, the UE  710  can determine the multiple RTTs. From the multiple RTTs, the UE  710  can determine its position. It is assumed that the UE  710  has knowledge of the locations of each of the gNBs  720 ,  730 ,  740  to enable the position of the UE  710  to be determined. The gNB locations may be provided to the UE  710  contemporaneously with the measurement quantities, provided by the network separately, and/or the UE  710  may have the locations stored within its memory storage. 
       FIGS. 8A and 8B  illustrate example flows of RTT measurement messages for UE-assisted multi-RTT positioning among a UE  810  (e.g., any of the UEs described herein), a primary gNB  820  (k=1), a secondary gNB  830  (k=2), and a neighboring gNB  840  (k=3). While one secondary gNB  830  is shown in each of  FIGS. 8A and 8B , there can be any number, i.e., zero or more, of secondary gNBs  830 . Also, while one neighboring gNB  840  is shown, there can be any number, i.e., zero or more, of neighboring gNBs  840 . It is nonetheless assumed that there is a plurality of gNBs. In  FIGS. 8A and 8B , it is assumed that an LCS resides in the primary gNB  820 . However, it should be noted that the LCS can reside in any serving gNB, e.g., in one of the secondary gNB  830 . 
     The primary gNB  820  determines the quantity Δ gNB   1 , each secondary gNB  830  determines its corresponding quantity Δ gNB   2 , and each neighboring gNB  840  determines its corresponding quantity Δ gNB   3 . The UE  810  determines the quantity Δ UE   1  associated with the primary gNB  820 , determines the quantity Δ UE   2  associated with each secondary gNB  830 , and determines the quantity Δ UE   2  associated with each neighboring gNB  840 . 
     In  FIGS. 8A and 8B , the primary gNB  820  gathers the cell RTT-related measurements from other gNBs and the UE RTT-related measurements from the UE  810 . That is, each secondary gNB  830  sends its Δ gNB   2  quantity to the primary gNB  820 , and each neighboring gNB  840  sends its Δ gNB   3  quantity to the primary gNB  820 . In an aspect, the UE  810  can send the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  to the primary gNB  820  (see  FIG. 8A ). For example, a physical uplink shared channel (PUSCH) and/or a physical uplink control channel (PUCCH) may be utilized to transmit the quantities to the primary gNB  820 . Alternatively, the UE  810  can send the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  to the secondary gNB  830  (see  FIG. 8B ), for example, in scenarios in which the non-coherent CoMP is in effect. The secondary gNB  830  in turn forwards the received quantities to the primary gNB  820 . Again, the PUSCH and/or the PUCCH may be utilized to transmit to the secondary gNB  830 . 
     In an aspect, the UE  810  can dynamically switch between sending the UE RTT-related measurements to the primary gNB  820  and sending them to the secondary gNB  830 . For example, in one instance, the primary gNB  820  can receive the quantities directly from the UE  810  for determining the position of the UE  810 . In the next instance, the primary gNB  820  can receive the quantities from the secondary gNB  830 . While not shown, the UE  820  may transmit the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  to multiple serving gNBs (any combination of the primary gNB  820  and/or the secondary gNBs  830 ) for diversity gain. 
     In  FIGS. 8A and 8B , the primary gNB  820  is in possession of its cell RTT-related measurement (quantity Δ gNB   1 ) through measurements. The primary gNB  820  also receives the cell RTT-related measurements (quantities Δ gNB   2 , Δ gNB   3 ) from other gNBs  830 ,  840  and receives the UE RTT-related measurements (quantities Δ UE   1 , Δ UE   2 , Δ UE   3 ) from the UE  810 . The primary gNB  820  can therefore determine the multiple RTTs. Along with the knowledge of the locations of the gNBs  820 ,  830 ,  840 , the primary gNB  820  can determine the position of the UE  810  from the multiple RTTs. 
       FIGS. 9A, 9B, 9C, and 9D  illustrate example flows of RTT measurement messages for UE-assisted multi-RTT positioning among a UE  910  (e.g., any of the UEs described herein), a primary gNB  920  (k=1), a secondary gNB  930  (k=2), a neighboring gNB  940  (k=3), and an LCS  950  (e.g., location server  230 , LMF  270 ). While one secondary gNB  930  is shown in each of  FIGS. 9A and 9B , there can be any number, i.e., zero or more, of secondary gNBs  930 . Also, while one neighboring gNB  940  is shown, there can be any number, i.e., zero or more, of neighboring gNBs  940 . It is nonetheless assumed that there is a plurality of gNBs. In  FIGS. 9A and 9B , it is assumed that the LCS  950  is external to any of the serving gNBs  920 ,  930 . 
     The primary gNB  920  determines the quantity Δ gNB   1 , each secondary gNB  930  determines its corresponding quantity Δ gNB   2 , and each neighboring gNB  940  determines its corresponding quantity Δ gNB   3 . The UE  910  determines the quantity Δ UE   1  associated with the primary gNB  920 , determines the quantity Δ UE   2  associated with each secondary gNB  930 , and determines the quantity Δ UE   3  associated with each neighboring gNB  940 . 
     In  FIGS. 9A and 9B , the UE  910  transmits the UE RTT-related measurements (quantities Δ UE   1 , Δ UE   2 , Δ UE   3 ) to a designated gNB. The designated gNB can be any of the serving gNBs the primary gNB  920  or the secondary gNBs  930 . The designated gNB is the gNB that has a communication connection with the UE  910 . In scenarios in which non-coherent CoMP is not in effect, the primary gNB  920  can be the designated gNB. On the other hand, in scenarios where non-coherent CoMP is in effect, a serving gNB (the primary gNB  920  or the secondary gNB  930 ) with the highest link quality can be chosen as the designated gNB. The link quality may be determined based on a channel state feedback (CSF) report and/or based on a RSRP/RSRQ report. 
     The designated gNB gathers the cell RTT-related measurements from other gNBs and forwards the gathered measurements to the LCS  950 . In  FIG. 9A , the primary gNB  920  is assumed to be the designated gNB (e.g., no non-coherent CoMP or the primary gNB  920  has the highest link quality). All other gNBs send their measurement quantities to the primary gNB  920 . That is, each secondary gNB  930  sends its Δ gNB   2  quantity to the primary gNB  920 . Also, each neighboring gNB  940  sends its Δ gNB   3  quantity to the primary gNB  920  or to the secondary gNB  930  to be forwarded to the primary gNB  920 . The UE  910  sends the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  to the primary gNB  920 . For example, the PUSCH and/or the PUCCH may be utilized to transmit the quantities to the primary gNB  920 . The primary gNB  920  sends its own Δ gNB   1  quantity along with the gathered Δ gNB   2 , Δ gNB   3 , Δ UE   1 , Δ UE   2 , Δ UE   3  to the LCS  950 . 
     In  FIG. 9B , the secondary gNB  930  is assumed to be the designated gNB (e.g., non-coherent CoMP and the secondary gNB  930  has the highest link quality). All other gNBs send their cell RTT-related measurements to the secondary gNB  930 . That is, the primary gNB  920  sends its Δ gNB   1  quantity to the designated secondary gNB  930 , each of the other secondary gNBs  930  sends its Δ gNB   2  quantity to the designated secondary gNB  930 , and each neighboring gNB  940  sends its Δ gNB   3  quantity to the designated secondary gNB  930 . The UE  910  sends the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  to the designated secondary gNB  930 . Again, the PUSCH and/or the PUCCH may be utilized. The primary gNB  920  sends its own Δ gNB   1  quantity along with the gathered Δ gNB   2 , Δ gNB   3 , Δ UE   1 , Δ UE   2 , Δ UE   3 , quantities to the LCS  950 . The designated secondary gNB  930  sends its own Δ gNB   2  quantity along with the gathered Δ gNB   1 , Δ gNB   2 , Δ gNB   3 , Δ UE   1 , Δ UE   2 , Δ UE   3  quantities to the LCS  950 . 
     In an aspect, the designated gNB can be switched dynamically. For example, in one instance, the primary gNB  920  can gather and send the measurement quantities to the LCS  950  to determine the position of the UE  910 . In the next instance of when the position of the UE  910  is to be determined, the secondary gNB  930  can gather and send the measurement quantities to the LCS  950 . 
     In  FIGS. 9C and 9D , the UE  910  also transmits the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  to a designated gNB. Again, the designated gNB can be any of the serving gNBs the primary gNB  920  or any of the secondary gNBs  930 . When non-coherent CoMP is not in effect, the primary gNB  930  can be the designated gNB. But when non-coherent CoMP is in effect, a serving gNB (the primary gNB  920  or the secondary gNB  930 ) with the highest link quality can be chosen as the designated gNB. The link quality may be determined based on a CSF report and/or based on a RSRP/RSRQ report. 
     In  FIGS. 9C and 9D , the measurement quantities gathering role of the designated gNB is reduced compared to that of the designated gNB of  FIGS. 9A and 9B . This is because in  FIGS. 9C and 9D , each gNB  920 ,  930 ,  940  sends its respective Δ gNB   1 , Δ gNB   2 , Δ gNB   3  quantity separately to the LCS  950 . The designated gNB does, however, gather the quantities Δ UE   1 , Δ UE   2 , Δ UE   3  from the UE  910  and forwards them to the LCS  950 . Again, the designated gNB can be switched dynamically. 
     In  FIGS. 9A, 9B, 9C, and 9D , the LCS  950  receives the cell RTT-related measurements (quantities Δ gNB   1 , Δ gNB   2 , Δ gNB   3 ) from the gNBs  920 ,  930 ,  940  and receives the UE RTT-related measurements (quantities Δ UE   1 , Δ UE   2 , Δ UE   3 ) from the UE  910  via the designated gNB. The LCS  950  can therefore determine the multiple RTTs from the received RTT-related measurements. The LCS  950  can determine the position of the UE  910  from the multiple RTTs with the knowledge of the locations of the gNBs  920 ,  930 ,  940 . 
       FIG. 10  illustrates an exemplary method  1000  performed by a positioning entity to determine the location of a UE (e.g., any of the UEs described herein). The positioning entity may be the UE itself, a serving cell (e.g., a serving gNB), or a location server external to the serving cell(s). At  1010 , the positioning entity gathers a plurality of cell RTT-related measurements (e.g., quantities Δ gNB   1 , Δ gNB   2 , Δ gNB   3 ). At  1020 , the positioning entity gathers a plurality of UE RTT-related measurements (e.g., quantities Δ UE   1 , Δ UE   2 , Δ UE   3 ). At  1030 , the positioning entity determines the UE position based on the gathered cell and UE RTT-related measurements. 
     In an aspect, regarding the plurality of cell RTT-related measurements, there can be one Δ gNB   1  quantity, zero or more Δ gNB   2  quantities, and zero or more Δ gNB   3  quantities. However, there are multiple cell RTT-related measurements. That is, the total number of cell RTT-related measurements is two or greater. Preferably, there are at least three (when determining the UE position in two dimensions) or at least four (when determining the UE position in three dimensions). The Δ gNB   1  quantity corresponds to the primary cell (e.g., primary gNB  720 ,  820 ,  920 ), each Δ gNB   2  corresponds to each secondary cell (e.g., secondary gNB  730 ,  830 ,  930 ), and each Δ gNB   3  corresponds to each neighboring cell (e.g., neighboring gNB  740 ,  840 ,  940 ). 
     In another aspect, regarding the plurality of UE RTT-related measurements, there can be one Δ UE   1  quantity, zero or more Δ UE   2  quantities, and zero or more Δ UE   3  quantities. However, there are multiple UE RTT-related measurements. That is, the total number of UE RTT-related measurements is two or greater. Preferably, there are at least three (to determine the UE position in two dimensions) or at least four (to determine the UE position in three dimensions). The Δ UE   1  quantity corresponds to the primary cell (e.g., primary gNB  720 ,  820 ,  920 ), each Δ UE   2  corresponds to each secondary cell (e.g., secondary gNB  730 ,  830 ,  930 ), and each Δ UE   3  corresponds to each neighboring cell (e.g., neighboring gNB  740 ,  840 ,  940 ). 
     In an aspect, the number of cell RTT-related measurements is equal to the number of UE RTT-related measurements. Moreover, each cell RTT-related measurement Δ gNB   k  corresponds to one UE RTT-related measurement Δ UE   k . For example, the quantity Δ gNB   1  corresponds to the quantity Δ UE   1 . In this way, the RTT associated with the primary cell may be determined. 
       FIG. 11  illustrates an exemplary process performed by a UE (e.g., any of the UEs described herein) to implement blocks  1010 ,  1020  of  FIG. 10  when the positioning entity is the UE. In an aspect at  1110 , the UE receives all of the cell RTT-related measurements (quantities Δ gNB   1 , Δ gNB   2 , Δ gNB   3 ) from a designated cell/TRP. This corresponds to the case 1.A identified above (see also  FIGS. 7A, 7B ). In this instance, the designated cell (e.g., primary gNB  720  or secondary gNB  730 ) gathers all of the cell RTT-related measurements and forwards them to the UE (e.g., UE  710 ). 
     The primary cell can be the designated cell when non-coherent CoMP is not in effect. On the other hand, when non-coherent CoMP is in effect, a serving cell (the primary cell or the secondary cell) with the highest link quality can be chosen as the designated cell. The link quality may be determined based on a CSF and/or a RSRP/RSRQ report. 
     In another aspect at  1110 , the UE receives all of the cell RTT-related measurements from multiple serving cells (e.g., the primary gNB  720  and/or the secondary gNBs  730 ) for diversity gain. In yet another aspect at  1110 , the UE receives the cell RTT-related measurements individually from each of the serving cells. This corresponds to the case 1.B identified above (see also  FIG. 7C ). That is, the UE receives Δ gNB   1  from the primary cell (e.g., primary gNB  720 ). When there are secondary cells (e.g., secondary gNBs  730 ), the UE receives Δ gNB   2  from each secondary cell. When there are neighboring cells (e.g., neighboring gNBs  740 ), the UE receives the corresponding Δ gNB   3  through one of the serving cells. 
     At  1120 , the UE gathers the UE RTT-related measurements through directly measuring the arrival times of the DL RS and the transmission times of the UL RS. In other words, the UE directly measures the T UE,Rx   k  and the corresponding T UE,Tx   k . 
       FIG. 12  illustrates an exemplary process performed by a primary cell (e.g., primary gNB  820 ) to implement blocks  1010 ,  1020  of  FIG. 10  when the primary cell is the positioning entity, i.e., when the location server resides in the primary cell. At  1210 , the primary cell measures its own associated cell RTT-related measurement Δ gNB   1 . That is, the primary cell directly measures the DL RS transmission time T gNB,Tx   1  and the corresponding UL RS reception time T gNB,Rx   1 . 
     At  1220 , the primary cell receives the cell RTT-related measurements Δ gNB   2 , Δ gNB   3  associated with other cells. For example, when there are secondary cells (e.g., secondary gNBs  830 ), the primary cell receives the Δ gNB   2  quantities from the secondary cells. Also, when there are neighboring cells (e.g., secondary gNBs  840 ), the primary cell receives the Δ gNB   3  quantities from the neighboring cells. This corresponds to the case 2.A identified above (see also  FIGS. 8A, 8B ). 
     At  1230 , the primary cell receives the UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the UE (e.g., UE  810 ). Alternatively, the primary cell receives the UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from one of the secondary cells. In this instance, the UE has sent the UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  to the secondary cell selected as having the highest link quality in scenarios when non-coherent CoMP is in effect, and the secondary cell is forwarding the received measurements to the primary cell. 
     In yet another alternative, the primary cell receives the UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the UE and from the secondary cell. In this instance, the UE may send the measurements to both the primary and the secondary cells for diversity gain. 
       FIG. 13  illustrates an exemplary process performed by the positioning entity to implement blocks  1010 ,  1020  when the positioning entity is separate, i.e., when the location server is outside of the serving cells. At  1310 , the positioning entity (e.g., the LCS  950 ) receives all of the plurality of cell RTT-related measurements (quantities Δ gNB   1 , Δ gNB   2 , Δ gNB   3 ) from a designated cell. This corresponds to the case 3.A identified above (see also  FIGS. 9A, 9B ). In this instance, the designated cell (e.g., primary gNB  920  or the secondary gNB  930 ) gathers all of the cell RTT-related measurements and forwards them to the positioning entity. 
     The primary cell can be the designated cell when non-coherent CoMP is not in effect. On the other hand, when non-coherent CoMP is in effect, a serving cell (the primary cell or the secondary cell) with the highest link quality can be chosen as the designated cell. The link quality may be determined based on a CSF and/or a RSRP/RSRQ report. 
     Alternatively, the positioning entity (e.g., the LCS  950 ) receives the cell RTT-related measurements individually from each of the primary, secondary, and neighboring cells. This corresponds to the case 3.B identified above (see also  FIGS. 9C and 9D ). That is, the positioning entity (e.g., the LCS  950 ) receives Δ gNB   1  from the primary cell (e.g., primary gNB  920 ), receives Δ gNB   2  from each secondary cell (e.g., secondary gNB  930 ) when there are secondary cells, and receives Δ gNB   3  from each neighboring cell (e.g., neighboring gNB  940 ) when there are neighboring cells. 
     At  1320 , the positioning entity (e.g., the LCS  950 ) receives the plurality of UE RTT-related measurements (quantities Δ UE   1 , Δ UE   2 , Δ UE   3 ) forwarded from the designated cell. Alternatively, the positioning entity (e.g., the LCS  950 ) receives the plurality of UE RTT-related measurements from the designated cell, and receives the same plurality of UE RTT-related measurements from another serving cell. This can be due to the UE sending the same of UE RTT-related measurements to multiple serving cells for diversity gain. 
     In the foregoing, the term “cell” has been used when describing the techniques disclosed herein. However, as will be appreciated, the term “cell” may be replaced with the term “TRP,” as a cell generally corresponds to a TRP and vice versa. 
       FIG. 14  illustrates an exemplary method  1400  in accordance with various aspects of the disclosure. The method  1400  may be performed by a positioning entity, such as a UE, a serving gNB, or a location server. The method  1400  generally corresponds to the method  1000  of  FIG. 10 . 
     At  1410 , the positioning entity gathers a plurality of TRP RTT-related measurements, the plurality of TRP RTT-related measurements being one-to-one associated with a plurality of TRPs, wherein each TRP RTT-related measurement is associated with one TRP of the plurality of TRPs. In an aspect, where the positioning entity is in a UE, operation  1410  may be performed by WWAN transceiver  310 , processing system  332 , memory  340 , and/or RTT measurement component  342 , any or all of which may be considered means for performing this operation. In an aspect, where the positioning entity is in a gNB, operation  1410  may be performed by WWAN transceiver  350 , processing system  384 , memory  386 , and/or RTT measurement component  388 , any or all of which may be considered means for performing this operation. In an aspect, where the positioning entity is in a network entity, operation  1410  may be performed by network interface(s)  390 , processing system  394 , memory  396 , and/or RTT measurement component  398 , any or all of which may be considered means for performing this operation. 
     At  1420 , the positioning entity gathers a plurality of UE RTT-related measurements, wherein each of the plurality of UE RTT-related measurements is associated with one TRP of the plurality of TRPs. In an aspect, where the positioning entity is in a UE, operation  1420  may be performed by WWAN transceiver  310 , processing system  332 , memory  340 , and/or RTT measurement component  342 , any or all of which may be considered means for performing this operation. In an aspect, where the positioning entity is in a gNB, operation  1420  may be performed by WWAN transceiver  350 , processing system  384 , memory  386 , and/or RTT measurement component  388 , any or all of which may be considered means for performing this operation. In an aspect, where the positioning entity is in a network entity, operation  1420  may be performed by network interface(s)  390 , processing system  394 , memory  396 , and/or RTT measurement component  398 , any or all of which may be considered means for performing this operation. 
     At  1430 , the positioning entity determines a position of a UE based on the plurality of TRP RTT-related measurements and the plurality of UE RTT-related measurements. In an aspect, for each TRP of the plurality of TRPs, the TRP RTT-related measurement associated with that TRP represents a duration between that TRP transmitting a DL RS to the UE and that TRP receiving a corresponding UL RS from the UE, and the UE RTT-related measurement associated with that TRP represents a duration between the UE receiving the DL RS from that TRP and the UE transmitting the corresponding UL RS to that TRP. In an aspect, where the positioning entity is in a UE, operation  1430  may be performed by processing system  332 , memory  340 , and/or RTT measurement component  342 , any or all of which may be considered means for performing this operation. In an aspect, where the positioning entity is in a gNB, operation  1430  may be performed by processing system  384 , memory  386 , and/or RTT measurement component  388 , any or all of which may be considered means for performing this operation. In an aspect, where the positioning entity is in a network entity, operation  1430  may be performed by processing system  394 , memory  396 , and/or RTT measurement component  398 , any or all of which may be considered means for performing this operation. 
       FIG. 15  illustrates an exemplary positioning entity  1500 , according to aspects of the disclosure. The positioning entity may correspond to a UE (e.g., UE  302 ), a base station (e.g., base station  304 ), or a network entity (e.g., network entity  306 ). 
     The positioning entity  1500  includes a module  1510  configured to gather a plurality of TRP RTT-related measurements, the plurality of TRP RTT-related measurements being one-to-one associated with a plurality of TRPs, wherein each TRP RTT-related measurement is associated with one TRP of the plurality of TRPs. In an aspect, where the positioning entity  1500  is in a UE, module  1510  may correspond to WWAN transceiver  310 , processing system  332 , memory  340 , and/or RTT measurement component  342 . In an aspect, where the positioning entity  1500  is in a gNB, module  1510  may correspond to WWAN transceiver  350 , network interface(s)  380 , processing system  384 , memory  386 , and/or RTT measurement component  388 . In an aspect, where the positioning entity  1500  is in a network entity, module  1510  may correspond to network interface(s)  390 , processing system  394 , memory  396 , and/or RTT measurement component  398 . 
     The positioning entity  1500  includes a module  1520  configured to gather a plurality of UE RTT-related measurements, wherein each of the plurality of UE RTT-related measurements is associated with one TRP of the plurality of TRPs. In an aspect, where the positioning entity  1500  is in a UE, module  1520  may correspond to WWAN transceiver  310 , processing system  332 , memory  340 , and/or RTT measurement component  342 . In an aspect, where the positioning entity  1500  is in a gNB, module  1520  may correspond to WWAN transceiver  350 , network interface(s)  380 , processing system  384 , memory  386 , and/or RTT measurement component  388 . In an aspect, where the positioning entity  1500  is in a network entity, module  1520  may correspond to network interface(s)  390 , processing system  394 , memory  396 , and/or RTT measurement component  398 . 
     The positioning entity  1500  includes a module  1530  configured to determine a position of a UE based on the plurality of TRP RTT-related measurements and the plurality of UE RTT-related measurements, wherein for each TRP of the plurality of TRPs, the TRP RTT-related measurement associated with that TRP represents a duration between that TRP transmitting a downlink reference signal (DL RS) to the UE and that TRP receiving a corresponding uplink reference signal (UL RS) from the UE, and the UE RTT-related measurement associated with that TRP represents a duration between the UE receiving the DL RS from that TRP and the UE transmitting the corresponding UL RS to that TRP. In an aspect, where the positioning entity  1500  is in a UE, module  1530  may correspond to WWAN transceiver  310 , processing system  332 , memory  340 , and/or RTT measurement component  342 . In an aspect, where the positioning entity  1500  is in a gNB, module  1530  may correspond to WWAN transceiver  350 , network interface(s)  380 , processing system  384 , memory  386 , and/or RTT measurement component  388 . In an aspect, where the positioning entity  1500  is in a network entity, module  1530  may correspond to network interface(s)  390 , processing system  394 , memory  396 , and/or RTT measurement component  398 . 
     In an aspect, the DL RS may be a PRS and/or the UL RS may be an SRS. 
     In an aspect, for each TRP k, the associated TRP RTT-related measurement is expressed as Δ gNB   k =T gNB,Rx   k −T gNB,Tx   k  in which T gNB,Tx   k  represents a transmission time of the DL RS from that TRP and T gNB,Rx   k  represents a reception time of the corresponding UL RS at that TRP, and the associated UE RTT-related measurement is expressed as Δ gNB   k =T gNB,Rx   k −T gNB,Tx   k  in which T UE,Rx   k  represents a reception time of the DL RS at the UE and T gNB,Tx   k  represents a transmission time of the corresponding UL RS from the UE, wherein the plurality of TRP RTT-related measurements comprise quantities one Δ gNB   1 , zero or more Δ gNB   2 , and zero or more Δ gNB   3  such that a total number of TRP RTT-related measurements is two or greater, the Δ gNB   1  corresponding to a primary TRP in data communication with the UE, each Δ gNB   2  corresponding to each secondary TRP in data communication with the UE, and each Δ gNB   3  corresponding to a neighboring TRP not in data communication with the UE, and wherein the plurality of UE RTT-related measurements comprise quantities one Δ UE   1 , zero or more Δ UE   2 , and zero or more Δ UE   3  such that a total number of UE RTT-related measurements is two or greater, the Δ UE   3  corresponding to the primary TRP, each Δ UE   2  corresponding to each secondary TRP, and each Δ UE   3  corresponding to each neighboring TRP. 
     In an aspect, for at least one TRP k, the T UE,Rx   k , T UE,Tx   k  measurements are derived from a received timing at the UE of a downlink radio subframe i from the TRP k defined by a first detected path in time, and a transmit timing at the UE of an uplink radio subframe i corresponding to the downlink radio subframe i, and/or the T gNB,Rx   k , T gNB,Tx   k  measurements are derived from a received timing at the TRP k of the uplink radio subframe i defined by a first detected path in time, and a transmit timing at the TRP k of the downlink radio subframe. 
     In an aspect, if the UE is the positioning entity, the module  1510  being configured to gather the plurality of TRP RTT-related measurements may comprise the module  1510  being configured to receive all of the plurality of TRP RTT-related measurements Δ gNB   1 , Δ gNB   2 , Δ gNB   3  from a designated TRP, the designated TRP being the primary TRP or a secondary TRP. In an aspect, the designated TRP may be the primary TRP when a non-coherent CoMP is not in effect, and the designated TRP may be a serving TRP among the primary and secondary TRPs with a highest link quality when the non-coherent CoMP is in effect. 
     In an aspect, if the UE is the positioning entity, the module  1510  being configured to gather the plurality of TRP RTT-related measurements may include the module  1510  being configured to receive individually the TRP RTT-related measurement Δ gNB   1 , Δ gNB   2  from each of the primary TRP and secondary TRPs. In an aspect, the module  1510  being configured to gather the plurality of TRP RTT-related measurements may further include the module  1510  being configured to receive the TRP RTT-related measurements Δ gNB   3  of the neighboring TRP through the primary TRP or the secondary TRP. 
     In an aspect, if the UE is the positioning entity, the module  1510  being configured to gather the plurality of TRP RTT-related measurements Δ gNB   1 , Δ gNB   2 , Δ gNB   3  may include the module  1510  being configured to receive all of the plurality of TRP RTT-related measurements Δ gNB   1 , Δ gNB   2 , Δ gNB   3  from the primary TRP, or to receive all of the plurality of TRP RTT-related measurements Δ gNB   1 , Δ gNB   2 , ΔgNB 3  from a secondary TRP. 
     In an aspect, if the UE is the positioning entity, the module  1520  being configured to gather the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  may include the module  1520  being configured to determine the UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UD   3  through direct measurements of the DL RS arrival times and the UL RS transmission times. 
     In an aspect, if the primary TRP is the positioning entity, the module  1510  being configured to gather the plurality of TRP RTT-related measurements may include the module  1510  being configured to determine the TRP RTT-related measurement Δ gNB   1  through direct measurements of the transmission time of the DL RS transmitted from the primary TRP and the reception time of the corresponding UL RS received from the UE, and to receive the TRP RTT-related measurement Δ gNB   2 , Δ gNB   3  from each secondary TRP and from each neighboring TRP. 
     In an aspect, if the primary TRP is the positioning entity, the module  1520  being configured to gather the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  may include the module  1520  being configured to receive the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the UE. 
     In an aspect, if the primary TRP is the positioning entity, the module  1520  being configured to gather the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  may include the module  1520  being configured to receive the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the secondary TRP. In an aspect, a non-coherent CoMP may be in effect, and the secondary TRP may be determined to have a higher link quality to the UE than the primary TRP. 
     In an aspect, if the primary TRP is the positioning entity, the module  1520  being configured to gather the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  may include the module  1520  being configured to receive the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the UE, or to receive the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the secondary TRP. 
     In an aspect, the positioning entity may be outside of any of the primary and secondary TRPs and outside of the UE. In that case, the module  1510  being configured to gather the plurality of TRP RTT-related measurements may include the module  1510  being configured to receive all of the plurality of TRP RTT-related measurements Δ gNB   1 , Δ gNB   2 , Δ gNB   3  from a designated TRP, the designated TRP being the primary TRP or a secondary TRP. The designated TRP may be the primary TRP when no non-coherent CoMP is in effect, and the designated TRP may be a serving TRP among the primary and secondary TRPs with a highest link quality when the non-coherent CoMP is in effect. In an aspect, the module  1510  being configured to gather the plurality of TRP RTT-related measurements may include the module  1510  being configured to receive individually the TRP RTT-related measurement Δ gNB   1 , Δ gNB   2 , A gNB   3  from each of the primary TRP, the secondary TRPs, and the neighboring TRPs. In an aspect, the module  1520  being configured to gather the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  may include the module  1520  being configured to receive all of the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from a designated TRP, the designated TRP being the primary TRP or one of the secondary TRP. The designated TRP may be the primary TRP when no non-coherent CoMP is in effect, and the designated TRP may be a serving TRP among the primary and secondary TRPs with a highest link quality when the non-coherent CoMP is in effect. In an aspect, the module  1520  being configured to gather the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  may include the module  1520  being configured to receive all of the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the primary TRP, or to receive all of the plurality of UE RTT-related measurements Δ UE   1 , Δ UE   2 , Δ UE   3  from the secondary TRP. 
     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.