Systems and methods for multi-round-trip time (RTT) estimation in a wireless network

Abstract

This application relates to systems and methods for multi-round-trip time (RTT) estimation in a wireless network. Techniques for determining the round-trip time (RTT) between a user equipment (UE) and multiple base stations are disclosed. In one aspect, the UE transmits an RTT measurement signal whose arrival time is measured by each of these base stations, and each of these base stations returns an RTT response signal whose arrival time is measured by the UE. In another aspect, each of these base stations transmits an RTT measurement signal, and the UE returns an RTT response signal. The receiver of the RTT measurement signal may include the measured arrival time in the payload of the RTT response signal. Alternatively, the measured arrival time of the RTT measurement signal(s) and the transmission time of the RTT response signal(s) are sent in a separate message. These RTT signals may be broadband signals using low-reuse resources.

Description

[0001] This application is a divisional application of the patent application with application number 201880081243.9, application date December 18, 2018, and invention name "Systems and Methods for Multi-Round Trip Time (RTT) Estimation in a Wireless Network".

[0002] Cross - reference to related applications

[0003] This patent application claims the benefit of U.S. Provisional Application No. 62 / 607,899, filed on December 19, 2017, entitled "ROUND TRIP TIME (RTT) ESTIMATION PROCEDURES", which has been assigned to the assignee of this application and is hereby incorporated by reference in its entirety.

[0004] Disclosure background

[0005] 1. Field of disclosure

[0006] Aspects of the present disclosure generally relate to telecommunications, and more particularly to round - trip time (RTT) estimation procedures in a wireless network.

[0007] 2. Description of related art

[0008] Wireless communication systems have evolved through several generations, including first - generation analog wireless telephone services (1G), second - generation (2G) digital wireless telephone services (including transitional 2.5G networks), third - generation (3G) high - speed data wireless services with Internet capabilities, and fourth - generation (4G) services (e.g., LTE or WiMax). There are currently many different types of wireless communication systems in use, including cellular and personal communication 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), Global System for Mobile access (GSM) TDMA variants, etc.

[0009] The fifth - generation (5G) wireless standard enables higher data transfer speeds, a larger number of connections, better coverage, and other improvements. According to the Next Generation Mobile Networks Alliance, the 5G standard is designed to provide data rates of tens of megabits per second to each of thousands of users, and data rates of 1 gigabit per second to dozens of employees in an office building. Hundreds or thousands of simultaneous connections should be supported to enable large - scale wireless sensor deployments. Therefore, compared to the current 4G standard, the spectral efficiency of 5G mobile communication should be significantly improved. In addition, compared to current standards, signaling efficiency should be improved and latency should be greatly reduced.

[0010] Overview

[0011] A simplified overview related to one or more aspects disclosed herein is provided below. Accordingly, the following overview should neither be considered an exhaustive survey of all contemplated aspects, nor should it be considered to identify key or critical elements related to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the sole purpose of the following overview is to present in a simplified form certain concepts related to one or more aspects regarding the mechanisms disclosed herein prior to the detailed description provided below.

[0012] In one aspect, a method for determining multiple round-trip times (RTTs) for a user equipment (UE) performed by a master node includes: transmitting an RTT measurement signal to the UE on a cell supported by the master node during one or more predefined symbols of a downlink subframe, receiving from the UE information indicating an arrival time of each of the multiple RTT measurement signals at the UE, where the multiple RTT measurement signals include the RTT measurement signal and multiple other RTT measurement signals transmitted by multiple other nodes;

[0013] receiving an RTT response signal from the UE, obtaining an arrival time of the RTT response signal at the master node, obtaining a transmission time of the RTT response signal, receiving from the multiple other nodes information indicating an RTT between the UE and each of the multiple other nodes, and determining the RTT between the UE and the master node and between the UE and each of the multiple other nodes based on at least one of: a transmission time of the RTT measurement signal at the master node, information indicating an arrival time of each of the multiple RTT measurement signals at the UE, an arrival time of the RTT response signal at the master node, a transmission time of the RTT response signal, information indicating an RTT between the UE and each of the multiple other nodes, and a timing adjustment parameter for the UE.

[0014] In one aspect, a method for determining multiple round-trip times (RTTs) at a user equipment (UE) includes: transmitting RTT measurement signals to a plurality of base stations, wherein each base station among the plurality of base stations measures an arrival time of the RTT measurement signal relative to a downlink subframe timing of each base station, receiving RTT response signals transmitted by each base station among the plurality of base stations, obtaining an arrival time of the RTT response signal received from each base station among the plurality of base stations at the UE, obtaining information regarding each base station among the plurality of base stations indicating a transmission time of the RTT response signal received from each base station and an arrival time of the RTT measurement signal measured by each base station, and calculating an RTT between the UE and each base station among the plurality of base stations based on a transmission time of the RTT measurement signal at the UE, an arrival time of the RTT response signal received from each base station among the plurality of base stations at the UE, information regarding each base station among the plurality of base stations indicating a transmission time of the RTT response signal received from each base station and an arrival time of the RTT measurement signal measured by each base station, and a timing adjustment parameter for the UE.

[0015] In one aspect, an apparatus for determining multiple RTTs for a UE includes: a communication device of a master node, configured to: transmit an RTT measurement signal to the UE on a cell supported by the master node during one or more predefined symbols of a downlink subframe, receive information indicating an arrival time of each RTT measurement signal among a plurality of RTT measurement signals at the UE, wherein the plurality of RTT measurement signals includes the RTT measurement signal and a plurality of other RTT measurement signals transmitted by a plurality of other nodes, and receive an RTT response signal from the UE; at least one processor of the master node, configured to: obtain an arrival time of the RTT response signal at the master node, and obtain a transmission time of the RTT response signal, wherein the communication device is further configured to: receive information indicating an RTT between the UE and each node among the plurality of other nodes from the plurality of other nodes, and wherein the at least one processor is further configured to: implement determination of an RTT between the UE and the master node and between the UE and each node among the plurality of other nodes based on at least one of the following: a transmission time of the RTT measurement signal at the master node, information indicating an arrival time of each RTT measurement signal among the plurality of RTT measurement signals at the UE, an arrival time of the RTT response signal at the master node, a transmission time of the RTT response signal, information indicating an RTT between the UE and each node among the plurality of other nodes, and a timing adjustment parameter for the UE.

[0016] In one aspect, an apparatus for determining multiple round-trip times (RTTs) at a user equipment (UE) includes: a transceiver of the UE configured to: transmit an RTT measurement signal to a plurality of base stations, wherein each base station of the plurality of base stations measures an arrival time of the RTT measurement signal relative to a downlink subframe timing of each base station, and receive an RTT response signal transmitted by each base station of the plurality of base stations; and at least one processor of the UE configured to: obtain an arrival time of the RTT response signal received from each base station of the plurality of base stations at the UE, obtain information regarding each base station of the plurality of base stations indicating a transmission time of the RTT response signal received from each base station and an arrival time of the RTT measurement signal measured by each base station, and calculate an RTT between the UE and each base station of the plurality of base stations based on a transmission time of the RTT measurement signal at the UE, the arrival time of the RTT response signal received from each base station of the plurality of base stations at the UE, the information regarding each base station of the plurality of base stations indicating the transmission time of the RTT response signal received from each base station and the arrival time of the RTT measurement signal measured by each base station, and a timing adjustment parameter for the UE.

[0017] In one aspect, an apparatus for determining multiple round-trip times (RTTs) for a user equipment (UE) includes: communication means of a master node configured to: transmit an RTT measurement signal to the UE on a cell supported by the master node during one or more predefined symbols of a downlink subframe, receive information indicating an arrival time of each RTT measurement signal of a plurality of RTT measurement signals at the UE, wherein the plurality of RTT measurement signals includes the RTT measurement signal and a plurality of other RTT measurement signals transmitted by a plurality of other nodes, and receive an RTT response signal from the UE; and processing means of the master node configured to: obtain an arrival time of the RTT response signal at the master node, and obtain a transmission time of the RTT response signal, wherein the communication means is further configured to: receive information indicating an RTT between the UE and each of the plurality of other nodes from the plurality of other nodes, and wherein the processing means is further configured to: implement a determination of the RTT between the UE and the master node and between the UE and each of the plurality of other nodes based on at least one of: a transmission time of the RTT measurement signal at the master node, the information indicating an arrival time of each RTT measurement signal of the plurality of RTT measurement signals at the UE, the arrival time of the RTT response signal at the master node, the transmission time of the RTT response signal, the information indicating an RTT between the UE and each of the plurality of other nodes, and a timing adjustment parameter for the UE.

[0018] In one aspect, an apparatus for determining multiple round-trip times (RTTs) at a user equipment (UE) includes: a communication device of the UE configured to: transmit an RTT measurement signal to a plurality of base stations, wherein each base station of the plurality of base stations measures an arrival time of the RTT measurement signal relative to a downlink subframe timing of each base station, and receive an RTT response signal transmitted by each base station of the plurality of base stations; and a processing device of the UE configured to: obtain an arrival time of the RTT response signal received from each base station of the plurality of base stations at the UE, obtain information regarding each base station of the plurality of base stations indicating a transmission time of the RTT response signal received from each base station and an arrival time of the RTT measurement signal measured by each base station, and calculate an RTT between the UE and each base station of the plurality of base stations based on a transmission time of the RTT measurement signal at the UE, the arrival time of the RTT response signal received from each base station of the plurality of base stations at the UE, the information regarding each base station of the plurality of base stations indicating the transmission time of the RTT response signal received from each base station and the arrival time of the RTT measurement signal measured by each base station, and a timing adjustment parameter for the UE.

[0019] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions for determining multiple round-trip times (RTTs) for a user equipment (UE) includes computer-executable instructions that include: at least one instruction to instruct a master node to transmit an RTT measurement signal to the UE on a cell supported by the master node during one or more predefined symbols of a downlink subframe; at least one instruction to instruct the master node to receive from the UE information indicating an arrival time of each of the multiple RTT measurement signals at the UE, where the multiple RTT measurement signals include the RTT measurement signal and multiple other RTT measurement signals transmitted by multiple other nodes; at least one instruction to instruct the master node to receive an RTT response signal from the UE; at least one instruction to instruct the master node to obtain an arrival time of the RTT response signal at the master node; at least one instruction to instruct the master node to obtain a transmission time of the RTT response signal; at least one instruction to instruct the master node to receive from the multiple other nodes information indicating an RTT between the UE and each of the multiple other nodes; and at least one instruction to instruct the master node to determine an RTT between the UE and the master node and between the UE and each of the multiple other nodes based on at least one of: a transmission time of the RTT measurement signal at the master node, information indicating an arrival time of each of the multiple RTT measurement signals at the UE, an arrival time of the RTT response signal at the master node, a transmission time of the RTT response signal, information indicating an RTT between the UE and each of the multiple other nodes, and a timing adjustment parameter for the UE.

[0020] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions for determining multiple round-trip times (RTTs) at a user equipment (UE) includes computer-executable instructions that include: at least one instruction instructing the UE to transmit an RTT measurement signal to a plurality of base stations, wherein each base station of the plurality of base stations measures an arrival time of the RTT measurement signal relative to a downlink subframe timing of the each base station, at least one instruction instructing the UE to receive an RTT response signal transmitted by each base station of the plurality of base stations, at least one instruction instructing the UE to obtain an arrival time of the RTT response signal received from each base station of the plurality of base stations at the UE, at least one instruction instructing the UE to obtain information regarding each base station of the plurality of base stations indicating a transmission time of the RTT response signal received from the each base station and an arrival time of the RTT measurement signal measured by the each base station, and at least one instruction instructing the UE to calculate an RTT between the UE and each base station of the plurality of base stations based on a transmission time of the RTT measurement signal at the UE, an arrival time of the RTT response signal received from each base station of the plurality of base stations at the UE, the information regarding each base station of the plurality of base stations indicating the transmission time of the RTT response signal received from the each base station and the arrival time of the RTT measurement signal measured by the each base station, and a timing adjustment parameter for the UE.

[0021] Based on the figures and the detailed description, other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings are presented to assist in describing aspects of the present disclosure, and are provided solely for illustration of these aspects and not for limitation thereof.

[0023] Figure 1A Illustrates a high-level system architecture of a wireless communication system according to one aspect of the present disclosure.

[0024] Figure 1B Illustrates an example configuration of a radio access network (RAN) of a cellular network and a packet-switched portion of a core network according to one aspect of the present disclosure.

[0025] Figure 2 Is a diagram illustrating an example of a frame structure for use in a wireless telecommunication system according to one aspect of the present disclosure.

[0026] Figure 3 Is a simplified block diagram of several exemplary aspects of components that may be employed in a wireless communication node and configured to support communication as taught herein.

[0027] Figure 4is a diagram illustrating an exemplary technique for determining the location of a mobile station using information obtained from multiple base stations.

[0028] Figure 5A and Figure 5B is a diagram showing exemplary timing within the RTT procedure that occurs during a wireless sounding request and response.

[0029] Figure 6 Illustrates an example of network - centric RTT estimation according to one aspect of the present disclosure.

[0030] Figure 7 Illustrates an example of UE - centric RTT estimation according to one aspect of the present disclosure.

[0031] Figure 8 Illustrates an exemplary system according to one aspect of the present disclosure, where the RTT estimation procedures disclosed herein are extended to massive multiple - input multiple - output (MIMO) and millimeter - wave (mmW) systems.

[0032] Figure 9 –12 illustrates an exemplary method for calculating the (an) RTT of a UE according to aspects of the present disclosure.

[0033] Figure 13 –16 are additional simplified block diagrams of several exemplary aspects of a device configured to support positioning and communication as taught herein.

[0034] Elements, phases, steps, and / or actions with the same reference numerals in different figures may correspond to each other (e.g., may be similar or identical to each other). Additionally, some elements in the various figures are labeled using a numerical prefix followed by a letter or numerical suffix. Elements with the same numerical prefix but different suffixes may be different instances of the same type of element. A numerical prefix without any suffix is used herein to refer to any element with that numerical prefix. For example, Figure 1A shows different instances 102 - 1, 102 - 2, 102 - 3, 102 - 4, 102 - 5, and 102 - N of a UE. A reference to UE 102 refers to any one of UE 102 - 1, 102 - 2, 102 - 3, 102 - 4, 102 - 5, and 102 - N. Similarly, in Figure 1A a reference to RAN 120 can refer to Figure 1A RAN 120A or RAN 120B in Detailed description

[0035] Aspects of the present disclosure are provided in the following description of various examples provided for illustrative purposes and the associated drawings. Alternative aspects may be devised without departing from the scope of the present disclosure. Additionally, elements that are well known in the art will not be described in detail or will be omitted so as not to obscure relevant details of the present disclosure.

[0036] The terms "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 superior or better than other aspects. Similarly, the term "aspects of the present disclosure" does not require that all aspects of the present disclosure include the discussed features, advantages, or modes of operation.

[0037] Those skilled in the art will appreciate that the information and signals described below can 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 referred to throughout the following description may be represented, in part, depending on the particular application, in part, on the desired design, in part, on the corresponding technology, etc., by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0038] In addition, many aspects are described in the form of sequences of actions performed by, for example, elements of a computing device. It will be recognized that the various actions described herein can be performed by special purpose circuitry (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of the two. Additionally, the sequences of actions described herein can be considered to be fully embodied within any form of non-transitory computer-readable storage medium having stored therein the corresponding set of computer instructions that, when executed, cause or direct the associated processor of the device to perform the functionality described herein. Thus, the various aspects of the present disclosure can be implemented in several different forms, all of which are contemplated as falling within the scope of the claimed subject matter. Additionally, for each aspect described herein, a corresponding form of any such aspect can be described herein as, for example, "logic configured to perform the described actions".

[0039] As used herein, the terms "user equipment" (UE) and "base station" are not intended to be dedicated to or otherwise limited to any particular radio access technology (RAT) unless otherwise specified. In general, a UE can be any wireless communication device (e.g., a mobile phone, router, tablet computer, laptop computer, tracking device, Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. The UE can be mobile or can be stationary (e.g., at certain times) and can communicate with a radio access network (RAN). As used herein, the term "UE" can be interchangeably referred to as "access terminal" or "AT", "client device", "wireless device", "subscriber equipment", "subscriber terminal", "subscriber station", "user terminal" or "UT", "mobile terminal", "mobile station", or variants thereof. Generally, a UE is capable of communicating with a core network via the RAN, and through the core network, these UEs can communicate with external networks (such as the Internet) and with other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as via a wired access network, a WiFi network (e.g., based on IEEE 802.11, etc.).

[0040] The base station can operate according to one of several RATs when communicating with the UE depending on the network in which it is deployed and can alternatively be referred to as an access point (AP), network node, B node, evolved B node (eNB), new radio (NR) B node (also referred to as gNB or g B node), etc. Additionally, in some systems, the base station can provide only edge node signaling functionality, while in other systems, the base station can provide additional control and / or network management functionality. The communication link by which the UE sends signals to the base station can be referred to as an uplink channel (e.g., reverse traffic channel, reverse control channel, access channel, etc.). The communication link by which the base station sends signals to the UE can be referred to as a downlink or forward link channel (e.g., paging channel, control channel, broadcast channel, forward traffic channel, etc.). As used herein, the term traffic channel (TCH) can refer to an uplink / reverse or downlink / forward traffic channel.

[0041] Figure 1A An advanced system architecture of a wireless communication system 100 in accordance with one aspect of the present disclosure is illustrated. The wireless communication system 100 includes UEs 1 to N (referred to as 102-1 to 102-N). The UEs 102-1 to 102-N can include cellular phones, personal digital assistants (PDAs), pagers, laptop computers, tablet computers, desktop computers, etc. For example, in Figure 1AIn [the figure], UE 102-1 and UE 102-2 are illustrated as cellular feature phones, UE 102-3, 102-4, and 102-5 are illustrated as cellular touchscreen phones or "smartphones", and UE 102-N is illustrated as a desktop computer or a personal computer (commonly referred to as a "PC"). Although Figure 1A only six UEs 102 are shown in [the figure], the number of UEs 102 in the wireless communication system 100 can be in the hundreds, thousands, or millions (e.g., N can be any number up to and including one million or greater).

[0042] Referring to Figure 1A , UEs 102-1 through 102-N are configured to communicate with one or more access networks (e.g., RANs 120A and 120B, access points 125, etc.) over a physical communication interface or layer (shown as air interfaces 104, 106, and 108 in Figure 1A [the figure]) and / or a direct wired connection. Air interfaces 104 and 106 may conform to a given cellular communication protocol (e.g., Code Division Multiple Access (CDMA), Evolution-Data Optimized (E-VDO), Enhanced High Rate Packet Data (eHRPD), Global System for Mobile Communications (GSM), Wideband CDMA (WCDMA), Long Term Evolution (LTE), LTE for Unlicensed Spectrum (LTE-U), 5th Generation (5G) New Radio (NR), etc.), while air interface 108 may conform to a Wireless Local Area Network (WLAN) protocol (e.g., IEEE 802.11). Both RANs 120A and 120B may include multiple access points that serve UEs over air interfaces such as air interfaces 104 and 106. The access points in RANs 120A and 120B may be referred to as access nodes (ANs), access points (APs), base stations (BSs), B nodes, evolved B nodes, gNBs, etc. For example, an eNodeB (also known as an evolved B node) is typically a base station that supports wireless access for UEs 102 according to the LTE radio interface defined by the 3rd Generation Partnership Project (3GPP). As another example, a g B node or gNB is typically a base station that supports wireless access for UEs 102 according to the 5G NR radio interface. These access points may be terrestrial access points (or ground stations) or satellite access points. Note that the terms "access point" and "base station" are used interchangeably herein.

[0043] Both RANs 120A and 120B are configured to be connected to the core network 140, which can perform a variety of functions - including routing and connecting circuit-switched (CS) calls between UEs 102 served by RAN 120A / 120B and other UEs 102 served by RAN 120A / 120B or by a different RAN, and can also arbitrate the exchange of packet-switched (PS) data with external networks (such as the Internet 175) and external clients and servers.

[0044] The Internet 175 includes several routing agents and processing agents (not shown for convenience in Figure 1A . In Figure 1A , UE 102-N is shown as being directly connected to the Internet 175 (i.e., separate from the core network 140, such as via an Ethernet connection over a WiFi- or IEEE 802.11-based network). The Internet 175 can thus be used to route and connect packet-switched data between UE 102-N and UEs 102-1 to 102-5 via the core network 140.

[0045] Figure 1A An access point 125 separate from RANs 120A and 120B is also shown in

[0046] . The access point 125 can be connected to the Internet 175 independently of the core network 140 (e.g., via an optical communication system such as FiOS, a cable modem, etc.). The air interface 108 can serve UEs 102-4 or UEs 102-5 through a local wireless connection (such as IEEE 802.11 in one example). UE 102-N is shown as a desktop computer having a wired connection to the Internet 175 (such as a direct connection to a modem or router), which in one example can correspond to the access point 125 itself (e.g., for a WiFi router having both wired and wireless connectivity).

[0046] Referring to Figure 1A , a location server 170 is shown as being connected to the Internet 175 and the core network 140. The location server 170 can be implemented as multiple structurally separate servers, or alternatively can correspond to a single server. As will be described in more detail below, the location server 170 is configured to support one or more location services for UEs 102, which can be connected to the location server 170 via the core network 140 and / or the Internet 175. When supporting the location of UEs 102 with 5G NR radio access (e.g., in the case where the core network 140 is a 5G core network or includes a 5G core network), the location server 170 can correspond to a Location Management Function (LMF).

[0047] Below with respect to Figure 1BExamples of protocol - specific implementations of RANs 120A and 120B and core network 140 are provided to help explain wireless communication system 100 in more detail. Specifically, the components of RANs 120A and 120B and core network 140 correspond to components associated with supporting packet - switched (PS) communication, where there may also be legacy circuit - switched (CS) components in these networks, but no legacy CS - specific components are explicitly shown in Figure 1B any of them.

[0048] Figure 1B An example configuration of a portion of RAN 120A and a portion of core network 140 based on an LTE network (also known as an evolved packet system (EPS)) according to an aspect of the present disclosure is illustrated. Referring to Figure 1B , RAN 120A is configured with multiple eNBs 202, 204, and 206. In Figure 1B the example, eNB 202 is shown as a home eNB (HeNB) and interfaces with RAN 120A via a HeNB gateway 245. HeNB 202 is an example of a “small cell base station” or “small cell”. The term “small cell” generally refers to a class of low - power base stations, which may include or otherwise be referred to as femtocells, picocells, microcells, home base stations, Wi - Fi APs, APs for other smaller coverage areas, etc. Small cells can be deployed to supplement macro - cell (e.g., eNB) coverage and / or increase network capacity. Small cells can provide wireless coverage indoors (such as within a house, office, part of a larger building, part of a convention center, mall, etc.). Small cells can alternatively or additionally provide wireless coverage outdoors (such as over an area covering a neighborhood block or part of several blocks). Relative to macro - cells, which typically communicate using licensed bands, small cells can communicate using unlicensed bands.

[0049] In Figure 1B , core network 140 includes an enhanced serving mobile location center (E - SMLC) 225, a mobility management entity (MME) 215, a gateway mobile location center (GMLC) 220, a serving gateway (S - GW) 230, a packet data network gateway (P - GW) 235, and a secure user plane location (SUPL) location platform (SLP) 240. The functions of E - SMLC 225 may include obtaining location measurements for UE 102 (e.g., from the UE 102 and / or from RAN 120), calculating the location of UE 102, and / or providing assistance data to UE 102 to enable the UE 102 to obtain location measurements and / or calculate a location estimate. In Figure 1B the example, Figure 1AThe location server 170 in may correspond to one or more of the E-SMLC 225, the GMLC 220, the SLP 240, or the SLP 260 accessible via the Internet 175.

[0050] The network interfaces between the components of the core network 140, RAN 120A, and the Internet 175 are Figure 1B , and are defined in Table 1 (below):

[0051]

[0052]

[0053] Table 1 - Core Network Connection Definition

[0054] Now Available Figure 1B 1 is a high-level description of some of the components shown in the RAN 120A and 120B and the core network 140. However, each of these components is well known in the art from various 3GPP and Open Mobile Alliance (OMA) technical specifications (TS), and the descriptions contained herein are not intended to be an exhaustive description of all functionality performed by these components.

[0055] Reference Figure 1B The MME 215 is configured to manage control plane signaling for the Evolved Packet System (EPS). MME functions include: Non-Access Stratum (NAS) signaling, NAS signaling security, mobility management of UE 102 (including support for inter-RAN and intra-RAN handover), P-GW and S-GW selection, and MME handover selection in the event of an MME change.

[0056] The S-GW 230 is a gateway that terminates the user plane interface towards the RAN 120A. For each UE 102 attached to the core network 140 of the LTE-based system, at a given point in time, there may be a single S-GW 230. The functions of the S-GW 230 include serving as a mobility anchor point, performing packet routing and forwarding, and setting a differentiated services code point (DSCP) based on the quality of service (QoS) class identifier (QCI) of the associated EPS bearer.

[0057] The P-GW 235 is the gateway that terminates the SGi interface towards the Packet Data Network (PDN) (e.g., the Internet 175). If the UE 102 is accessing multiple PDNs, there may be more than one P-GW 235 for that UE 102. The P-GW 235 functions include: providing PDN connectivity to the UE 102, UE IP address allocation, setting the DSCP based on the QCI of the associated EPS bearer, accounting for inter-operator charging, uplink (UL) and downlink (DL) bearer binding, and UL bearer binding verification.

[0058] As Figure 1B further explained in, the external client 250 can be connected to the core network 140 via the GMLC 220 and / or the SLP 240. The external client 250 can optionally be connected to the core network 140 and / or the SLP 260 via the Internet 175. The external client 250 can be a server, a web server, or a user device such as a personal computer, a UE, etc.

[0059] Figure 1B The HeNB gateway 245 in can be used to support the connection of small cells and / or HeNBs (such as the HeNB 202). The HeNB gateway 245 can include or be connected to a security gateway ( Figure 1B not shown in). The security gateway can help authenticate the small cells and / or HeNBs (such as the HeNB 202), and / or can enable secure communication between the small cells and / or HeNBs (such as the HeNB 202) and other network entities (such as the MME 215). The HeNB gateway 245 can perform protocol relay and conversion to allow the small cells and / or HeNBs (such as the HeNB 202) to communicate with other entities (such as the MME 215).

[0060] The GMLC 220 can be a location server that enables an external client (such as the external client 250) to request and obtain a location estimate of the UE 102. The functions of the GMLC 220 can include: authenticating and authorizing the external client 250, and requesting and obtaining a location estimate of the UE 102 from the MME 215 on behalf of the external client 250.

[0061] The SLP 240 and SLP 260 can support the Secure User Plane Location (SUPL) location solution defined by the Open Mobile Alliance (OMA), which is a user plane (UP) location solution. In the case of using the UP location solution, interfaces and protocols that support the transmission of data (and possibly voice and other media) can be used to transmit the signaling for initiating and performing the positioning of the UE 102. In the case of using the SUPL UP location solution, the location server can include a SUPL Location Platform (SLP) (such as the SLP 240 or SLP 260) or take the form of an SLP. In Figure 1B this case, either or both of the SLP 240 and 260 can be the Home SLP (H-SLP), Emergency SLP (E-SLP), and / or Discovered SLP (D-SLP) for one or more UEs 102. The functions of the SLP 240 and 260 can include some or all of the functions previously described for the E-SMLC 225 and GMLC 220.

[0062] The network for providing 5G NR radio access to the UE 102 can be similar to the example wireless communication system 100 described above for Figure 1B but there may also be certain differences. Specifically, in a 5G network: the eNBs 204 and 206 and the HeNB 202 can each be replaced by gNBs that provide NR radio access to the UE 102; there may be no HeNB gateway 245; the MME 215 can be replaced by an Access and Mobility Management Function (AMF) connected to these gNBs and a Session Management Function (SMF) connected to the AMF, and the AMF and the SMF together perform functions similar to those of the MME 215; both the S-GW 230 and P-GW 235 can be replaced by a User Plane Function (UPF) that performs functions similar to those performed by both the S-GW 230 and P-GW 235; the E-SMLC 225 can be replaced by an LMF that performs functions similar to or the same as those of the E-SMLC 225; and the GMLC 220 can be retained and continue to perform functions the same as or similar to those previously described. Different 5G core functionalities (such as location management functions, access and mobility functions, security anchor functions, session management functions, authentication server functions, etc.) can be implemented in a somewhat distributed manner, where some functionalities are performed by the same network device and certain functionalities are performed by different network devices; and can be implemented in different network devices (compared to the implementation of similar functions in the 4G core network).

[0063] The time intervals of communication resources in LTE or 5G NR can be organized according to radio frames. Figure 2An example of a downlink radio frame structure 200 according to one aspect of the present disclosure is explained. However, as will be readily appreciated by those skilled in the art, the frame structure for any particular application may vary depending on any number of factors. In this example, a frame 201 (10 ms) is divided into 10 equally sized subframes 203 (1 ms). Each subframe 203 includes 2 consecutive time slots 205 (0.5 ms).

[0064] A resource grid can be used to represent the 2 time slots 205, and each time slot 205 includes a resource block 207. The resource grid is divided into a plurality of resource elements. In LTE, and in some cases in 5G NR, a resource block contains 12 consecutive subcarriers 209 in the frequency domain, and for a normal cyclic prefix in each OFDM symbol 211, contains 7 consecutive OFDM symbols 211 in the time domain, that is, contains 84 resource elements. Some resource elements indicated as R0 and R1 include downlink reference signals (DL-RS). DL-RS includes cell-specific RS (CRS) (sometimes also referred to as common RS) and UE-specific RS (UE-RS). UE-RS is only transmitted on the resource blocks to which the corresponding physical downlink shared channel (PDSCH) is mapped. The number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks 207 the UE receives and the higher the modulation scheme, the higher the data rate of the UE.

[0065] LTE and in some cases 5G NR utilize OFDM on the downlink and single-carrier frequency-division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also often referred to as frequency tones, frequency slots, etc. Each subcarrier can be modulated with data. Generally, modulation symbols are transmitted in the frequency domain for OFDM and in the time domain for SC-FDM. The interval between adjacent subcarriers can be fixed, and the total number (K) of subcarriers can depend on the system bandwidth. For example, the subcarrier interval can be 15 kHz, and the minimum resource allocation (resource block) can be 12 subcarriers (or 180 kHz). Thus, for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048 respectively. The system bandwidth can also be divided into subbands. For example, a subband can cover 1.08 MHz (i.e., 6 resource blocks), and for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, there can be 1, 2, 4, 8, or 16 subbands respectively.

[0066] Figure 3Several example components (represented by the respective boxes) that can be incorporated into apparatuses 302, 304, and 306 (e.g., corresponding to a UE, a base station (e.g., gNB), and a network entity or location server, respectively, for example) to support operations as taught herein are illustrated. As an example, apparatus 302 may correspond to UE 102, apparatus 304 may correspond to any one of eNBs 202 - 206 or gNBs, and apparatus 306 may correspond to E - SMLC 225, SLP 240, SLP 260, GMLC 220, or LMF. It will be appreciated that these components may be implemented in different types of apparatuses (e.g., ASICs, system - on - chips (SoCs), etc.) in different implementations. The illustrated components may also be incorporated into other apparatuses in the communication system. For example, other apparatuses in the system may include components similar to those described to provide similar functionality. Additionally, a given apparatus may include one or more of these 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.

[0067] Each of apparatuses 302 and 304 includes at least one wireless communication device (represented by communication devices 308 and 314) for communicating with other nodes via at least one specified RAT (e.g., LTE, 5G NR). Each communication device 308 includes at least one transmitter (represented by transmitter 310) for transmitting and encoding signals (e.g., messages, indications, information, etc.) and at least one receiver (represented by receiver 312) for receiving and decoding signals (e.g., messages, indications, information, pilots, etc.). Each communication device 314 includes at least one transmitter (represented by transmitter 316) for transmitting signals (e.g., messages, indications, information, pilots, etc.) and at least one receiver (represented by receiver 318) for receiving signals (e.g., messages, indications, information, etc.).

[0068] In some implementations, the transmitter and receiver may include integrated devices (e.g., transmitter circuitry and receiver circuitry implemented as a single communication device), in some implementations may include separate transmitter devices and separate receiver devices, or may be implemented otherwise in other implementations. In one aspect, the transmitter may include multiple antennas, such as an antenna array, which permits the corresponding device to perform transmit "beamforming", as further described herein. Similarly, the receiver may include multiple antennas, such as an antenna array, which permits the corresponding device to perform receive beamforming, as further described herein. In one aspect, the transmitter and receiver may share the same multiple antennas such that the corresponding device can only receive or transmit at a given time, rather than both simultaneously. The wireless communication device of apparatus 304 (e.g., one of a plurality of wireless communication devices) may also include a network listening module (NLM) for performing various measurements, etc.

[0069] Apparatus 304 and apparatus 306 include at least one communication device (represented by communication device 320 and communication device 326) for communicating with other nodes. For example, communication device 326 may include a network interface (e.g., one or more network access ports) configured to communicate with one or more network entities via a wired-based backhaul connection or a wireless backhaul connection. In some aspects, communication device 326 may be implemented as a transceiver configured to support wired-based signal communication or wireless signal communication. The communication may involve, for example, sending and receiving: messages, parameters, or other types of information. Accordingly, in Figure 3 the example, communication device 326 is shown to include a transmitter 328 and a receiver 330 (e.g., network access ports for transmitting and receiving). Similarly, communication device 320 may include a network interface configured to communicate with one or more network entities via a wired-based backhaul or a wireless backhaul. Like communication device 326, communication device 320 is shown to include a transmitter 322 and a receiver 324.

[0070] Devices 302, 304, and 306 also include other components that can be used in conjunction with the operations disclosed herein. Device 302 includes a processing system 332 for providing functionality related to RTT measurements in licensed or unlicensed bands as disclosed herein, for example, and for providing other processing functionality. Device 304 includes a processing system 334 for providing functionality related to RTT measurements in licensed or unlicensed bands as disclosed herein, for example, and for providing other processing functionality. Device 306 includes a processing system 336 for providing functionality related to RTT measurements in licensed or unlicensed bands as disclosed herein, for example, and for providing other processing functionality. In one aspect, processing systems 332, 334, and 336 can include, for example, one or more general-purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGAs), or other programmable logic devices or processing circuitry.

[0071] Devices 302, 304, and 306 each include memory components 338, 340, and 342 (e.g., each including a memory device) for maintaining information (e.g., information indicating reserved resources, thresholds, parameters, etc.). Additionally, devices 302, 304, and 306 each include user interface devices 344, 346, and 348 for providing indications to a user (e.g., audible and / or visual indications) and / or for receiving user input (e.g., when the user actuates a sensing device such as a keypad, touch screen, microphone, etc.).

[0072] For convenience, devices 302, 304, and 306 are shown in Figure 3 as including various components that can be configured according to the various examples described herein. However, it will be appreciated that the illustrated blocks can have different functionality in different designs.

[0073] Figure 3 The components of can be implemented in various ways. In some implementations, Figure 3The various components of can be implemented in one or more circuits, such as, by way of 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 308, 332, 338, and 344 may be implemented by the processor and (one or more) memory components of device 302 (e.g., by executing appropriate code and / or by appropriately configuring the processor components). Similarly, some or all of the functionality represented by blocks 314, 320, 334, 340, and 346 may be implemented by the processor and (one or more) memory components of device 304 (e.g., by executing appropriate code and / or by appropriately configuring the processor components). Additionally, some or all of the functionality represented by blocks 326, 336, 342, and 348 may be implemented by the processor and (one or more) memory components of device 306 (e.g., by executing appropriate code and / or by appropriately configuring the processor components).

[0074] In one aspect, device 304 may correspond to a "small cell" or home eNB, such as Figure 1B the home eNB 202 in . Device 302 may transmit and receive messages via wireless link 360 to device 304, the messages including information related to various types of communications (e.g., voice, data, multimedia services, associated control signaling, etc.). Wireless link 360 may operate on a communication medium of interest (shown as medium 362 in Figure 3 , which may be shared with other communications and other RATs). This type of medium may include one or more frequency, time, and / or space communication resources associated with communications between one or more transmitter / receiver pairs (such as between device 304 and device 302 for medium 362) (e.g., covering one or more channels across one or more carriers).

[0075] As a specific example, the medium 362 may correspond to at least a portion of an unlicensed band shared with other RANs and / or other APs and UEs. In general, the apparatuses 302 and 304 may operate via the wireless link 360 according to one or more radio access types (such as LTE, LTE-U, or 5G NR) depending on the network in which they are deployed. These networks may include, for example, different variants of CDMA networks (such as LTE networks, 5G NR networks, etc.), TDMA networks, FDMA networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, and the like. Although different licensed bands have been reserved for wireless communications (e.g., reserved by government entities such as the Federal Communications Commission (FCC) in the United States), certain communication networks (especially those employing small cell base stations) have extended their operations to unlicensed bands, such as the unlicensed national information infrastructure (U-NII) bands used by WLAN technologies (most notably the IEEE 802.11x WLAN technologies generally referred to as "Wi-Fi"), and LTE in unlicensed spectrum technologies generally referred to as "LTE-U" or "MuLTEFire".

[0076] The apparatus 302 may also include an RTT measurement component 352, which may be used to obtain location-related measurements of signals (such as RTT or other signals) transmitted by a base station or an AP (e.g., any one of the eNBs 202-206 or gNBs 502 and 622-626) according to the techniques described herein. The location-related measurements may include measurements of the signal propagation time or RTT between the UE 102 and a base station or an AP (such as any one of the eNBs 202-206 and gNBs 502, 622-626).

[0077] The apparatuses 304 and 306 may each include an RTT measurement component 354 and 356, respectively, which may be used to determine a location estimate of the UE 102 (e.g., the apparatus 302) based on location-related measurements provided by the UE 102 and / or by a base station or an AP (such as any one of the eNBs 202-206 or gNBs) according to the techniques described herein. The location-related measurements obtained by the UE 102 may include measurements of the signal propagation time or RTT between the UE 102 and a base station or an AP (such as any one of the eNBs 202-206 or gNBs). The location-related measurements obtained by any one of the eNBs 202-206 (e.g., the apparatus 304) may include measurements of the signal propagation time or RTT between the UE 102 and a base station or an AP (such as any one of the eNBs 202-206 or gNBs).

[0078] Figure 4A simplified environment is shown for explaining an exemplary technique for determining the location of UE 102. UE 102 can wirelessly communicate with multiple eNBs 202 - 206 using radio frequency (RF) signals and standardized protocols for RF signal modulation and information packet exchange. By extracting different types of information from the exchanged signals and leveraging the layout of the network (i.e., network geometry), UE 102 can determine its position in a predefined reference coordinate system. As Figure 4 shown, UE 102 can use a two - dimensional coordinate system to specify its position (x, y); however, aspects disclosed herein are not limited to this, and can also be applicable to using a three - dimensional coordinate system to determine the position in cases where additional dimensions are desired. Additionally, although Figure 4 3 eNBs 202 - 206 are shown, aspects can utilize additional eNBs.

[0079] To determine its position (x, y), UE 102 may first need to determine the network geometry. The network geometry can include the position ((x k , y k ) of each of eNBs 202 - 206 in the reference coordinate system, where k = 1, 2, 3). The network geometry can be provided to UE 102 in any way, such as, for example, providing this information in a beacon signal, using a dedicated external server on an external network to provide this information, using a uniform resource identifier to provide this information, and so on.

[0080] Then, UE 102 can determine the distance (d k , where k = 1, 2, 3) to each of eNBs 202 - 206. As will be described in more detail below, there are several different methods for estimating these distances (d k ) by leveraging different characteristics of the RF signals exchanged between UE 102 and eNBs 202 - 206. Such characteristics can include the round - trip propagation time of these signals and / or the strength (RSSI) of these signals, as will be discussed below.

[0081] In other aspects, other information sources not associated with eNBs 202 - 206 can be used to partially determine or refine these distances (d k ). For example, other positioning systems (such as GPS) can be used to provide a rough estimate of d k . (Note that GPS is likely to have insufficient signal strength in the expected operating environments (indoors, urban areas, etc.) to provide an accurate estimate of d kAn always accurate estimate. However, GPS signals can be combined with other information to assist in this location determination process.) Other relative positioning devices (such as, for example, an on-board accelerometer) that can be used as a basis for providing a rough estimate of relative position and / or orientation can reside in the UE 102.

[0082] Once each distance is determined, the UE 102 can then solve for its position (x, y) by using a variety of known geometric design techniques (such as, for example, trilateration). From Figure 4 it can be seen that the position of the UE 102 ideally lies at the common intersection of all the circles drawn with dashed lines. Each circle is defined by a radius d k and a center (x k , y k ), where k = 1, 2, 3. In practice, due to noise and other errors in the networking system, the intersection of these circles may not lie at a single point.

[0083] Determining the distance between the UE 102 and each eNB 202 - 206 can involve using the time information of RF signals. In one aspect, it can be performed to determine the RTT of the signals exchanged between the UE 102 and any eNB 202 - 206 and convert this RTT into a distance (d k ). Such RTT techniques can measure the time between sending a signaling message and receiving a response. These methods can utilize calibration to remove any processing delays. In some environments, it can be assumed that the processing delays of the UE 102 and the eNB 202 - 206 are the same. However, such an assumption may vary in practice.

[0084] In a variant of the technique shown in Figure 4 , each of the eNBs 202 - 206 can be replaced by a gNB. In this variant, the principle of the technique can remain as previously described, where the UE 102 is located at the common intersection of the circles, and where each circle is centered on one of these gNBs and has a radius obtained from the measurement of the RTT between the UE 102 and that gNB.

[0085] In some instances (such as, for example, as described later for Figure 8 ), additional information in the form of an angle of arrival (AOA) or an angle of departure (AOD) can be obtained, which defines a straight-line direction (for example, the straight-line direction can be in a horizontal plane, or in three-dimensional space) or a range of possible directions (for example, the range of directions of the UE 102 as seen from the position of the gNB or eNB). Figure 4Two such exemplary linear directions 402 and 404 from eNBs 202 and 206 respectively are illustrated in []. The intersection of these two directions 402 and 404 at point 406 can provide another estimate of the location of UE 102. Additionally, the intersection of a direction from an eNB or gNB with a circle (or sphere) around that eNB or gNB or around another eNB or gNB can provide another estimate of the location of UE 102. For example, Figure 4 Point 408 in [] illustrates the intersection of direction 402 with a circle (or sphere) around eNB 202. The location estimates provided by directions from gNBs or eNBs can be further combined with the location estimates provided by RTT to improve the location estimate of UE 102, as is known in the art.

[0086] Location estimates (e.g., for UE 102) can be referred to by other names, such as position estimates, positions, localizations, location fixings, fixings, etc. A location estimate can be geodetic and include coordinates (e.g., latitude, longitude, and possibly altitude), or can be civic and include a street address, postal address, or some other verbal location description. A location estimate can be further defined relative to some other known location or in absolute terms (e.g., using latitude, longitude, and possibly altitude). A location estimate can include an expected error or uncertainty (e.g., by including an area or volume within which the location is expected to contain a specified or default confidence level).

[0087] Figure 5A FIG. 500 is a diagram showing exemplary timing within an RTT measurement that occurs during a wireless sounding request and response. In one aspect, the response can take the form of an acknowledgment packet (ACK); however, any type of response packet will be compliant with aspects of the present disclosure. For example, a request to send (RTS) transmission packet and / or a clear to send (CTS) response packet can be suitable. Figure 5A is illustrated as using gNB 502, but any one of eNBs 202 - 206 can substitute Figure 5A for gNB 502 in [], without changing the measurement procedure.

[0088] To measure the RTT for a given gNB 502, UE 102 can send a directed sounding request (PR) packet to that gNB 502 and record the time (timestamp) at which the sounding request packet (“t TX packet”) is sent, as shown on the UE 102 timeline in Figure 5A During the propagation time t of the sounding request packet between UE 102 and gNB 502 PAfter that, gNB 502 will receive the packet (assuming line-of-sight (LOS) propagation). Then, gNB 502 can process the directional sounding request packet and send an ACK back to UE 102 after some processing time Δ, as shown in the gNB 502 timeline in Figure 5A . After a second propagation time t p , UE 102 can record the time (timestamp) at which it receives the ACK packet (“t RX ACK”), as shown in the UE 102 timeline. Then, UE 102 can determine the RTT as the time difference t RX ACK - t TX packet. However, the RTT obtained in this way may include an error component due to the processing time Δ, which may not always be accurately known. The distance D between UE102 and gNB 502 can be obtained as (RTT / c), where c is the radio signal propagation speed (usually the speed of light). The distance D can then be used to determine the circle or sphere around gNB 502 on which UE 102 may be located (e.g., as in Figure 4 ).

[0089] Current positioning methods used in cellular networks (such as observed time difference of arrival (OTDOA)) typically require fine (e.g., sub-microsecond level) timing synchronization across the base stations in the network. On the other hand, RTT-based methods may only require coarse timing synchronization (e.g., within the cyclic prefix (CP) duration of an orthogonal frequency division multiplexing (OFDM) symbol). This disclosure describes procedures that can be implemented in a 5G NR network, which utilize its self-contained subframe structure (which enables transmission and ACK / NACK in the same subframe) and avoid the need for fine synchronization of base stations.

[0090] In 5G NR, precise timing synchronization across the network is not required. Instead, (coarse) CP-level time synchronization across gNBs is sufficient. Coarse time synchronization can achieve low reuse of RTT measurement signals, which mitigates inter-cell interference. Inter-cell interference mitigation ensures deep penetration of RTT signals, which enables multiple independent timing measurements across different gNBs and thus more accurate positioning.

[0091] In network - centric RTT estimation, the serving gNB instructs the UE (e.g., UE 102) to scan / receive RTT measurement signals from one or more neighboring gNBs (and typically also the serving gNB). The one or more gNBs transmit the RTT measurement signals on low - reuse resources (i.e., resources used by the base station to transmit system information) allocated by the network (e.g., location server 170). The UE records the arrival time (also referred to as reception time, receive time, receive time, or arrival time) of each RTT measurement signal relative to the UE's current downlink timing (e.g., derived by the UE from the DL signal received from its serving gNB), and transmits a common or individual RTT response message to the one or more gNBs (e.g., when instructed by its serving gNB), and may include each measured arrival time in the payload of the (these) RTT response message.

[0092] UE - centric RTT estimation is similar to the network - based method, except that: the UE (e.g., UE 102) transmits (these) uplink RTT measurement signals (e.g., when instructed by the serving gNB), which are received by multiple gNBs in the vicinity of the UE. Each gNB responds with a downlink RTT response message, which may include the arrival time of the RTT measurement signal at the gNB in the RTT response message payload.

[0093] For both network - centric and UE - centric procedures, the side (network or UE) that performs the RTT calculation typically (but not always) transmits (these) first messages or signals (e.g., (these) RTT measurement signals), and the other side responds with one or more RTT response messages or signals, which may include the arrival (or reception) time of the first message or signal in the RTT response message payload.

[0094] Figure 5B FIG. 550 is a diagram showing exemplary timings within the RTT measurement that occur during a wireless sounding request and response, where the RTT calculation can be more accurate than the Figure 5A RTT calculation in. In Figure 5B entity E1 552 corresponds to a UE (e.g., UE 102) or a gNB (e.g., gNB 502), and entity E2 554 corresponds to the other of the UE and the gNB. For network - centric RTT estimation, E1 552 may correspond to the gNB, and E2 554 may correspond to the UE. For UE - centric RTT estimation, E1 552 may correspond to the UE, and E2 554 may correspond to the gNB. In Figure 5BIn this figure, the straight-line distance D between E1 552 and E2 554 is represented vertically, while time is represented horizontally, with time increasing from left to right. The transmission time and reception time at E1 552 are shown at the bottom of the diagram 550, and the transmission time and reception time at E2 554 are shown at the top of the diagram 550. In the case of a gNB, the transmission and reception timings will typically be the same. In the case of a UE, the transmission timing will typically lead (i.e., exceed) the reception timing by an amount referred to as "timing advance" or "timing adjustment" (often abbreviated as TA) such that the UE transmission timing is approximately consistent with the gNB reception timing from the perspective of the serving gNB or arrives at the serving gNB at some other preferred time. To compensate for this difference, the known TA value can be subtracted from any transmission time of the UE, as shown in more detail below.

[0095] Figure 5B The timing at E2 554 in this figure is assumed to be earlier than the timing at E1 552 by an amount δ (but can be later than the timing at E1 552 if δ is negative). This assumption allows for both a synchronized network (e.g., where δ can be zero) and a non-synchronized or asynchronous network (where δ can have any value). Assume that E1 552 transmits an RTT measurement signal (or message) 562 at time Tx0 at E1 552 (and thus at time Tx0 + δ at E2 554), and this signal (or message) 562 is received at time Rx0 at E2 554 (and thus at time Rx0 – δ at E1 552). Later, E2 554 transmits an RTT response message or signal 564 at time Tx1 at E2 554 (and thus at time Tx1 – δ at E1 552), and this message or signal 564 is received at time Rx1 at E1 552 (and thus at time Rx1 + δ at E2 554). The equations below the diagram 550 assume that any TA compensation has occurred and show how the RTT can be obtained from the transmission and reception times Tx0, Rx0, Tx1, and Rx1 based on well-known modulo arithmetic rules. Specifically, if the RTT is less than 1 millisecond (ms) (which would mean that the distance D between the UE and the gNB is less than 150 kilometers, which is very likely to occur in any 5G network), it is possible to measure the transmission time and arrival time relative to the 1 ms NR subframe timing by using the value modulo 1 ms. This can simplify the measurement because it is not necessary to measure, record, or transmit integer multiples of 1 ms.

[0096] Figure 5B The entity E1 552 in this figure (or some other entity to which E1 552 forwards its measurements) can use the measured Tx0 and Rx1 values and the Rx0 and Tx1 values, according to Figure 5BThe RTT is determined using Equation 570 in []. The values of Rx0 and Tx1 can be obtained by E1 552 according to one of four replacement variants (herein labeled V1, V2, V3, and V4). In variant V1, entity E2 554 includes the measured Rx0 value in the payload of the RTT response 564, and entity E1 552 measures the transmission time Tx1 according to the NR subframe and radio frame structure of the RTT response 564. Then, entity E1 552 can determine the RTT from the known values of Rx0, Rx1, Tx0, and Tx1 (e.g., using Equation 570). Variant V1 may require entity E1 552 to both demodulate and decode the RTT response 564 (to measure Tx1 and obtain Rx0 from the payload). However, this may not always be possible if entity E1 552 and E2 554 are far from each other (e.g., for a UE that is 5 kilometers or more away from an outdoor gNB in an urban or suburban environment) or if there is strong interference from other radio sources (e.g., other UEs and / or gNBs) at E1 552. In contrast, in the case of using variants V2, V3, and V4 (described below), E1 552 does not necessarily always need to demodulate and decode the RTT response 564 (e.g., it may only be necessary to sufficiently demodulate the RTT response 564 to measure the arrival time Rx1), which enables the measurement of weaker signals and / or interfered signals.

[0097] In the case of using variant V2, when E2 554 is a UE, the time Rx0 and Tx1 at E2 554 are sent from the UE to the serving gNB in a separate message (e.g., an RRC message); or when E2 554 is a gNB, the time Rx0 and Tx1 at E2 554 are sent from the serving gNB to the UE in a separate message (e.g., an RRC message). The serving gNB of the UE can further send or receive the Rx0 and Tx1 values (or indications of the Rx0 and Tx1 values) to or from the gNB for which the RTT is to be obtained when this gNB is not the serving gNB. Although variant V2 ensures the correct transmission of Rx0 and Tx1, the additional separate messages may add both extra delay and require more signaling.

[0098] In the case of using variant V3 (which is only applicable when E2 554 is a UE), the UE includes the measured Rx0 in the payload of the RTT response 564, and the serving gNB of the UE (rather than other gNBs) demodulates and decodes the RTT response 564 to obtain the Rx0 measurement and measures Tx1. Then, if necessary, the serving gNB can forward the Rx0 and Tx1 values to the gNB for which the RTT is being measured.

[0099] In the case of utilizing variant V4 (which is also applicable only when E2 554 is a UE), E1 552 (which is a gNB) or the UE's serving gNB when E1 552 is not the UE's serving gNB sends the required Tx1 value (e.g., which may be adjusted to include or exclude TA) to the UE in advance, which means that the gNB (or serving gNB) knows the Tx1 value in advance. E1 552 (or serving gNB) may use a separate message to send the value of Tx1, or may include Tx1 in the payload of the RTT measurement message (or signal) 562. In the case of utilizing variant V4, the Rx0 value may be sent by the UE in the payload of the RTT response 564 or in a separate message. When E1 552 is a UE, a portion of variant V4 may also be used to send the required Tx0 value to the UE in a separate message before the UE transmits the RTT measurement message (or signal) 562. By using variant V4 to know the value of Tx1 or Tx0 in advance, the gNB may be able to more accurately measure Rx1 or Rx0, respectively, because it is approximately known when the RTT message or signal (562 or 564) from the UE will arrive. The gNB may also indicate to the UE in advance the expected value of Tx0 or Tx1 at the gNB, which may help improve the UE's measurement of Rx0 or Rx1, respectively.

[0100] The above-described method for Figure 5B The described RTT procedure enables determination of multiple RTTs. In order to improve signaling efficiency for multiple gNBs and reduce the number of separate measurements, the RTT measurement message or signal 562 (when E1 552 is a UE) or the RTT response message or signal 564 (when E2 554 is a UE) may be sent only once and measured by all participating gNBs. In this case, the transmission time of the single RTT message or signal (which will be Tx0 or Tx1) only needs to be provided or measured once (for example, measured only by the serving gNB or sent only to the serving gNB by the UE). In addition, for variants V1 and V3, when E2 554 is a UE, the UE may include the Rx0 values of all gNBs in the payload of the RTT response signal 564. Alternatively, when E1 552 is a UE, the serving gNB may (after transmitting the RTT response 564) send the Rx0 values of all gNBs (and optionally the transmission time Tx1 of all gNBs) to the UE in a single message. To optimize the transmission of both Rx0 and Tx1 values in a single message, only the value of (Rx0 − Tx1 ) (modulo 1 ms) needs to be sent, as can be seen in equation 570 .

[0101] For network - centric RTT estimation where E2 552 is a gNB, RTT calculation for a non - serving gNB can only be performed at the non - serving gNB when using variant V1. For other variants (V2 - V4) and in some cases for variant V1, the non - serving gNB may transmit information indicating the RTT (e.g., values of Tx0 and Rx1 or a single (Rx1–Tx0) value) to another entity (such as the serving gNB of the UE, or a location server), which can then calculate the RTT or transmit the information to another entity where the RTT calculation may occur (e.g., a location server). The entity performing the RTT calculation (or receiving the calculated RTT) can further obtain the location of the UE - for example, as described for Figure 4 as described.

[0102] To compensate for the TA value (assumed to have occurred in the equation shown in Figure 5B ), when E1 552 is a UE, the UE can simply subtract the TA value from the transmission time of the RTT measurement signal 562 to obtain the value of Tx0 used in equation 570. When E2 554 is a UE and using variant V1 or variant V3, the transmission time Tx1 determined by E1 552 will be incorrect and will exceed the correct value of Tx1 by the amount TA. To compensate, the UE can add the TA value to the Rx0 value sent to E1 552 in the payload of the RTT response 564. Alternatively, for any of these variants, the UE can send the TA value to the serving gNB (if the serving gNB does not have the TA value), and the network side can adjust Tx1 by subtracting the TA value. All these additions and subtractions can be performed modulo 1 ms.

[0103] Figure 6 and Figure 7 provide additional examples of determining the RTT at which the timing at the gNB and UE can be aligned. These examples illustrate additional details of the signaling and procedures. Figure 6 and Figure 7 The examples in Figure 5B can apply to variant V1 described above for Figure 5B . But can also apply to other variants. A single RTT response message directed to a specific gNB(i) includes the (a) timestamp(s) (Δt(i)+TA) in its payload, where Δt(i) represents the arrival time of the RTT measurement signal received from gNB(i), and TA represents the UE's uplink timing adjustment parameter. A common RTT response message includes a set of timestamps (Δt(i)+TA) in its payload corresponding to the RTT measurement signals from all measured gNBs. These timestamps (Δt(i)+TA) can be organized in other ways known to those skilled in the art.

[0104] The network may allocate low-reuse resources to the UE to transmit the (an) RTT response message. In any case, each gNB(i) that receives an RTT response message will record the arrival time ΔT(i) of the RTT response message at the gNB(i) relative to the downlink time reference of the gNB(i). The gNB(i) may calculate the RTT between the UE and itself by adding the timestamp value (Δt(i)+TA) to the arrival time ΔT(i). This calculation may be performed at each gNB that receives the RTT response from the UE or at a central location in the network (e.g., location server 170 or serving gNB).

[0105] Figure 6 An example of a network-centric RTT estimation technique in accordance with an aspect of the present disclosure is illustrated. As Figure 6 shown, on a downlink-centric / downlink-only subframe 602 (with a low duty cycle), the serving gNB 622 transmits a control signal to the UE 102 during the first two symbol periods of the downlink subframe 602 (e.g., on the physical downlink control channel (PDCCH)), thereby indicating to the UE 102 that one or more gNBs ( Figure 6 the serving gNB 622, gNB 624, and gNB 626 in the example) will transmit a downlink RTT measurement (RTTM) signal.

[0106] During downlink subframes 606 and 608, the gNBs 624 and 626 transmit the downlink RTT measurement signals in a time-division multiplexing (TDM) or frequency-division multiplexing (FDM) manner (as illustrated by the horizontal subdivision of each symbol of the downlink subframes 606 and 608) at the designated (designated by the network (e.g., location server 170 or serving gNB 622)) symbols of the downlink subframes 606 and 608. Although not illustrated, the serving gNB 622 may also transmit a downlink RTT measurement signal (also referred to as an RTT measurement signal) during the downlink subframe 602. The downlink RTT measurement signals transmitted by the gNBs 622-626 may be wideband signals to enable the UE 102 to perform accurate timing measurements. No other nearby gNB shall transmit other signals within or around the symbols associated with these downlink RTT measurement signals (resulting in low reuse of the RTT measurement signals, interference avoidance, and deep penetration of the RTT measurement signals).

[0107] During downlink subframe 604, UE 102 measures the arrival time Δt(i) of each downlink RTT measurement signal transmitted by gNBs 624 and 626 during downlink subframes 606 and 608 relative to its own downlink subframe timing. UE 102 derives its downlink subframe timing from the downlink signal received from serving gNB 622 on the PDCCH. That is, UE 102 sets the start time of its PDCCH subframe to the time when it receives the downlink signal from serving gNB 622.

[0108] UE 102 is instructed to report, during a subsequent uplink subframe, its RTT measurement (i.e., arrival time measurement Δt(i)) of the RTT measurement signal transmitted by gNBs 622 - 626 on the physical uplink shared channel (PUSCH) during uplink subframe 612. This uplink RTT report from UE 102 (also referred to as the RTT response) may include the arrival time Δt(i) of each measured downlink RTT measurement signal (where the RTT report is a "common" report) and the UE 102's own uplink timing adjustment (TA) provided by serving gNB 622. Like the downlink RTT measurement signals transmitted by gNBs 622 - 626, the uplink RTT report transmitted by UE 102 should be a wideband signal so that each gNB can make accurate timing measurements of its arrival. Each gNB in the neighborhood of UE 102 (i.e., each gNB within the communication range of UE 102; in Figure 6 the example of Figure 6 is gNBs 622 - 626) receives the uplink RTT report from UE 102. In

[0109] the example, gNB 624 receives the uplink RTT report from UE 102 during uplink subframe 614. Each gNB(i) decodes the uplink RTT report from UE 102 and records the corresponding arrival time ΔT(i) of the uplink RTT report from UE 102 relative to its own system time. Then, each gNB(i) can calculate the RTT between that gNB(i) and UE 102 based on the arrival time of the uplink RTT report from UE 102, in combination with the timing information in the payload (i.e., the arrival time of the RTT measurement and the timing adjustment).

[0109] Note that the timing adjustment is a parameter that takes into account the distance between the UE 102 and the serving gNB 622. More specifically, the timing adjustment is the time to prevent collisions with neighboring UEs starting from the time slot (e.g., OFDM symbol 211) when the UE 102 is permitted to transmit a traffic burst. The timing adjustment enables all uplink signals from the UE 102 to reach the serving gNB 622 simultaneously. The uplink timing adjustment enables the uplink RTT report to reach with the required accuracy at the end of the gap following the PDCCH.

[0110] UE-centered RTT estimation is similar to the above-described network-based method, except that: the UE (e.g., UE 102) transmits (when instructed) one or more uplink RTT measurement signals, which are received by multiple gNBs in the neighborhood of the UE. Each gNB (i) responds with a downlink RTT response message that includes the arrival time Δt(i) of the RTT measurement signal from the UE in the message payload to the gNB (i). The UE determines the arrival time ΔT(i) of the downlink RTT response message from each gNB (i), decodes the RTT response message and the timing estimate, extracts the timestamp Δt(i) embedded in the message, and calculates the RTT for the responding gNB (i) by adding the measured arrival time ΔT(i), the extracted timestamp Δt(i), and its own uplink-downlink timing adjustment (TA) value.

[0111] Figure 7 An example of a UE-centered RTT estimation technique according to an aspect of the present disclosure is illustrated. On an uplink-centered subframe 702 (with a low duty cycle), the serving gNB 622 (e.g., on the PDCCH) sends a control signal to the UE 102, instructing the UE 102 (and possibly any number of other UEs) to transmit one or more uplink RTT measurement signals (UL-RTTM).

[0112] During the uplink subframe 704, the UE 102 uses the designated resource blocks (RBs) in the uplink data portion of the uplink subframe 704 to transmit one or more RTT measurement signals (as specified by the serving gNB 622) in a TDM or FDM manner (as illustrated by the horizontal subdivision of the respective symbols of the uplink subframe 704). The RTT measurement signal(s) can be a wideband signal to enable more accurate timing measurements. No UE in the neighborhood is permitted to transmit other signals on the symbols associated with the uplink RTT measurement signal(s) (resulting in low reuse, interference avoidance, and deep penetration of the RTTM).

[0113] During uplink subframes 706 and 708, each gNB in the neighborhood (i.e., each gNB within the communication range of UE 102; gNBs 622 - 626 in the example of Figure 7 measures the arrival time Δt(i) of each received uplink RTT measurement signal at the respective gNB(i) relative to its own downlink subframe timing (assuming synchronous deployment of the gNBs). The serving gNB 622 instructs UE 102 to scan / receive downlink RTT responses from gNBs 622 - 626 on subsequent downlink subframes, which in the example of Figure 7 occur during downlink subframes 714 and 716. The downlink RTT response from each gNB 622 - 626 includes the arrival time Δt(i) of the uplink RTT measurement signal from UE 102 at the respective gNB(i). In one aspect, the RTT response should be a broadband signal so that UE 102 can perform accurate timing measurements.

[0114] UE 102 and each UE in the neighborhood (e.g., some or all UEs within the communication range of gNBs 622 - 626) decodes the RTT responses from gNBs 622 - 626 during downlink subframe 712 and also measures the arrival time ΔT(i) of the downlink RTT response from the respective gNB(i) in gNBs 622 - 626 relative to its own (downlink) system time.

[0115] The RTT for UE102 can be calculated based on the arrival time of the downlink RTT response at UE 102, combined with the timing information (i.e., arrival time Δt(i)) in the downlink RTT response along with its own timing adjustment (provided by the serving gNB). Any mismatch between the inter - gNB timings can be absorbed into 0.5RTT(0); precise timing synchronization across gNBs 622 - 626 is not required in 5G NR.

[0116] The RTT estimation procedure disclosed herein can be extended to massive multiple - input multiple - output (MIMO) and to the extremely high - frequency (EHF) region of the spectrum (also known as millimeter - wave (mmW) (typically bands above 24 GHz) systems). In mmW band systems and massive MIMO systems in any band, the gNB uses transmit / receive beamforming to extend the signal coverage to the cell edge.

[0117] Transmit "beamforming" is a technique for focusing RF signals in a specific direction. Traditionally, when a base station broadcasts an RF signal, it broadcasts the signal omnidirectionally (in all directions) or over a wide angular range (e.g., over a cellular cell sector). In the case of using transmit beamforming, the base station determines where a given target device (e.g., UE 102) is located (relative to the base station) and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal to the receiving device(s). To change the directivity of the RF signal during transmission, the base station can control the phase and relative amplitude of the RF signal at each transmitter. For example, the base station can use an antenna array (referred to as a "phased array" or "antenna array") that generates a beam of RF waves, and the beam of RF waves can be "steered" in different directions without actually moving the antennas. Specifically, the RF currents from the transmitters are fed to the individual antennas with the correct phase relationships such that the radio waves from the separate antennas add together in the desired direction to increase radiation, while canceling in the undesired directions to suppress radiation.

[0118] In receive beamforming, the receiver uses a receive beam to amplify the RF signal 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 specific direction to amplify the RF signal received from that direction (e.g., to increase its gain level). Thus, when a receiver is said to perform beamforming in a certain direction, it means that the beam gain in that direction is high relative to the beam gains in other directions, or that the beam gain in that direction is the highest compared to the beam gains in the directions of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), signal-to-noise-and-interference ratio (SINR), etc.) for the RF signal received from that direction.

[0119] The term "cell" refers to a logical communication entity used for communicating with a base station (e.g., on a carrier), and can be associated with an identifier (e.g., physical cell identifier (PCID), virtual cell identifier (VCID)) used to distinguish adjacent cells operating via the same or different carriers. In some examples, a carrier can support multiple cells, and different cells can be configured according to different protocol types (e.g., machine type communication (MTC), narrowband Internet of Things (NB-IoT), enhanced mobile broadband (eMBB), or other protocols) that can provide access for different types of devices. In some cases, the term "cell" can refer to a portion of the geographical coverage area over which the logical entity operates (e.g., a sector).

[0120] Figure 8An exemplary system in accordance with one aspect of the present disclosure is described, where the RTT estimation procedures disclosed herein are extended to massive MIMO and mmW systems. In Figure 8 the example of, gNBs 622-626 are massive MIMO gNBs. To perform the RTT estimation procedures described herein in a massive beamforming system (e.g., MIMO, mmW), each physical gNB (e.g., gNBs 622-626) acts as a group of multiple "logical gNBs" and transmits its RTT measurement signals or RTT response signals on multiple beams (e.g., beams 1-4) in a TDM or FDM manner on different time-frequency resources. The RTT measurement / response signals may (implicitly or explicitly) carry information about the identity of the gNB transmitting the signal and the beam index (e.g., 1-4) used to transmit them. The UE (e.g., UE 102) processes the RTT (measurement / response) signals received on the downlink as if they were transmitted by different gNBs. Specifically, in addition to the previously described timestamps (e.g., arrival time), the UE also records or reports the beam index (or beam indices) or other beam identities (or other beam identities) of the received RTT signals. The recorded beam index (or beam indices) can be used to identify the downlink (DL) beams measured by UE 102 and determine the associated angle of departure (AOD) from the transmitting gNB towards each identified DL beam of UE 102. The AOD can be used to determine the estimated direction from the gNB to UE 102.

[0121] During reception, gNBs 622-626 record / report the received beam index (or other received beam identities) of the RTT (measurement / response) signals received from UE 102 and include this information, along with the previously described timestamps (e.g., arrival time), in the RTT response payload (for UE-centric RTT estimation). Similar to the DL beams measured and identified by UE 102, the received beam indices recorded (and reported) by gNBs 622-626 can be used to determine the associated angle of arrival (AOA) from the receiving gNB towards each identified received beam of UE 102. The AOA can be used to determine the estimated direction from the gNB to UE 102.

[0122] As described above, when the AOA and / or AOD are available for the UE, the position of the UE can be calculated by using the RTT, AOD, and / or AOA to improve the position determination of the UE based on RTT as described for Figure 4 (e.g., making it more accurate).

[0123] If any of gNBs 622 - 626 has fewer RF chains than the number of receive beams used by that gNB (since a single hardware receiver chain can be configured to generate multiple receive beams), the UE 102 may be commanded to repeat the RTT measurement / response message multiple times so that the gNB can sequentially cycle through the entire set of receive beams that can be used to receive the RTT signal from the UE 102 based on its limited baseband processing capabilities. An RF chain can be a receiver chain or a transmitter chain and is the hardware for receiving or transmitting RF signals at a given frequency or set of frequencies. More specifically, a receiver chain includes the hardware components of a single hardware receiver among the multiple hardware receivers of the device and may include a receive antenna, radio, and modem. Similarly, a transmitter chain includes the hardware components of a single hardware transmitter among the multiple hardware transmitters of the device and may include a transmit antenna, radio, and modem. A device (e.g., gNB 622 - 626 or UE 102) may have multiple receiver / transmitter chains and may thus be able to transmit and / or receive RF signals simultaneously at multiple frequencies.

[0124] In one aspect, in a (massive) MIMO system, either or both of gNBs 622 - 626 and UE 102 may repeat their RTT measurement / report signals multiple times. Different repetitions may use the same or different transmission beams.

[0125] When repeating the signal with the same transmission beam, it is intended to support receive beam sweeping (plus coherent combining if needed) at the receiving end point (UE 102 or a gNB 622 - 626).

[0126] In one aspect, the angle of arrival (AOA) / angle of departure (AOD) associated with beam index information (at gNB 622 - 626) may be used in combination with RTT estimation to calculate the geographical location of the UE (RTT plus AOA / AOD - based positioning).

[0127] Figure 9 An exemplary method 900 for calculating the RTT of a UE (e.g., UE 102) performed by a master node (such as a serving base station or a non - serving base station (e.g., any of gNBs 502, 622 - 626)) is illustrated. Method 900 may be performed by, for example Figure 3The communication device 314 and / or the processing system 334 of the apparatus 304 therein are performed based on the execution of the RTT measurement component 354. At 902, the master node (e.g., the communication device 314) transmits a plurality of downlink RTT measurement signals to the UE 102 on a corresponding plurality of cellular cells supported by the master node during one or more predefined symbols of a downlink subframe. At 904, the master node (e.g., the communication device 314) sends a command to the UE 102 to report the arrival time of each of the plurality of downlink RTT measurement signals. At 906, the master node (e.g., the communication device 314 or the processing system 334 from the communication device 314) receives an uplink RTT report from the UE 102, the uplink RTT report including the arrival time of each of the plurality of downlink RTT measurement signals relative to the downlink subframe timing of the UE and the uplink timing adjustment parameter of the UE. At 908, the master node (e.g., the processing system 334) calculates the RTT between the UE and the master node based on the combination of the arrival times of the plurality of downlink RTT measurement signals, the timing adjustment parameter, and the arrival time of the uplink RTT report at the master node relative to the system time of the master node.

[0128] Figure 10 Illustrates an exemplary method 1000 for calculating RTT at a UE (e.g., UE 102). The method 1000 may be performed by, for example Figure 3 the communication device 308 and / or the processing system 334 therein based on the execution of the RTT measurement component 352.

[0129] At 1002, the UE 102 (e.g., the communication device 308 or the processing system 332 from the communication device 308) receives a control signal from a first base station (e.g., any one of gNBs 502 and 622 - 626), the control signal instructing the UE to transmit an uplink RTT measurement signal during a predefined resource block of a subframe. In one aspect, the UE 102 receives the control signal on the PDCCH. In one aspect, the uplink RTT measurement signal includes a broadband signal. In one aspect, the first base station is the serving base station of the UE 102.

[0130] At 1004, the UE 102 (e.g., the communication device 308 or the processing system 332 of the communication device 308) transmits an uplink RTT measurement signal to one or more base stations (e.g., any one of gNBs 502, 622 - 626) during a predefined resource block of a subframe, wherein at least one of the one or more base stations measures the arrival time of the uplink RTT measurement signal relative to the downlink subframe timing of the at least one base station. In one aspect, the one or more base stations are neighbor base stations of the first base station within the communication range of the UE.

[0131] At 1006, the UE 102 (e.g., the communication device 308 or the processing system 332 from the communication device 308) receives a downlink RTT response from the at least one base station, the downlink RTT response including the arrival time of the uplink RTT measurement signal. In one aspect, the UE 102 receives a downlink RTT response including the arrival time of the uplink RTT measurement signal from each of the one or more base stations.

[0132] At 1008, the UE 102 (e.g., the communication device 308) calculates the RTT between the UE 102 and the at least one base station based on the arrival time of the downlink RTT response at the UE 102, the timing adjustment parameter of the UE 102, and the arrival time of the uplink RTT measurement signal relative to the downlink system time of the UE 102. The UE 102 receives an uplink timing adjustment parameter from the first base station. In one aspect, the RTT is the sum of the arrival time of the downlink RTT response, the timing adjustment parameter, and the arrival time of the uplink RTT measurement signal relative to the downlink system time of the UE 102.

[0133] Figure 11 An exemplary method 1100 for determining multiple RTTs for a UE (such as a serving base station or a non-serving base station (e.g., any of the gNBs 502, 622 - 626)) in accordance with aspects of the present disclosure is illustrated. The method 1100 may be performed by, for example Figure 3 the communication device 314 and / or the processing system 334 of the apparatus 304 in

[0134] At 1102, the master node (e.g., the communication device 314) transmits an RTT measurement signal to the UE on a cell supported by the master node during one or more predefined symbols of a downlink subframe.

[0135] At 1104, the master node (e.g., communication device 314) receives from the UE information indicating the arrival time at the UE of each of a plurality of RTT measurement signals, where the plurality of RTT measurement signals includes the RTT measurement signal and a plurality of other RTT measurement signals transmitted by a plurality of other nodes. In one aspect, the plurality of other nodes may be neighboring base stations within the communication range of the UE. In one aspect, the plurality of RTT measurement signals may be broadband signals. In one aspect, the plurality of RTT measurement signals may be transmitted on low-reuse resources. In one aspect, the master node and at least one of the plurality of other nodes transmit at least one of the plurality of RTT measurement signals on one or more transmit beams, where the UE reports the identity of at least one of the one or more transmit beams, and the identity of the at least one transmit beam enables determination of the AOD for the UE.

[0136] At 1106, the master node (e.g., communication device 314) receives an RTT response signal from the UE. In one aspect, the RTT response signal may be transmitted on low-reuse resources. In one aspect, the master node and at least one of the plurality of other nodes receive the RTT response on one or more receive beams, and the identity of the at least one receive beam enables determination of the AOA for the UE. In one aspect, the master node and at least one of the plurality of other nodes utilize a plurality of receive beams, and based on the master node and the at least one of the plurality of other nodes having fewer hardware receiver chains than the number of the plurality of receive beams, the UE transmits the RTT response multiple times to allow the master node and the at least one of the plurality of other nodes to sequentially cycle through all of the plurality of receive beams that can be used to receive the RTT response from the UE. In one aspect, the master node sends a command to the UE to transmit the RTT response multiple times.

[0137] At 1108, the master node (e.g., processing system 334) obtains the arrival time of the RTT response signal at the master node.

[0138] At 1110, the master node (e.g., processing system 334) obtains the transmission time of the RTT response signal. In one aspect, obtaining the transmission time of the RTT response signal may include at least one of the following: (1) determining the transmission time of the RTT response signal based on the content of the RTT response signal, (2) receiving the transmission time of the RTT response signal in a separate message from the UE, or (3) the master node determines the transmission time of the RTT response signal and sends the transmission time of the RTT response signal to the UE before the transmission time of the RTT response signal.

[0139] At 1112, the master node (e.g., communication device 314) receives information indicating the RTT between the UE and each of the plurality of other nodes from the plurality of other nodes. In one aspect, the information indicating the RTT between the UE and each of the plurality of other nodes may include information indicating the transmission time of each RTT measurement signal transmitted by the plurality of other nodes and information indicating the arrival time of the RTT response signal at each of the plurality of other nodes.

[0140] At 1114, the master node (e.g., communication device 314 or processing system 334) determines the RTT between the UE and the master node and between the UE and each of the plurality of other nodes based on at least one of the following: the transmission time of the downlink RTT measurement signal at the master node, information indicating the arrival time of each of the plurality of RTT measurement signals at the UE, the arrival time of the RTT response signal at the master node, the transmission time of the RTT response signal, information indicating the RTT between the UE and each of the plurality of other nodes, and the timing adjustment parameter for the UE.

[0141] In one aspect, the implementation at 1114 includes: performing the determination at the master node. In one aspect, the implementation at 1114 includes: sending to a location server at least one of the following: the transmission time of the downlink RTT measurement signal at the master node, information indicating the arrival time of each of the plurality of RTT measurement signals at the UE, the arrival time of the RTT response signal at the master node, the transmission time of the RTT response signal, information indicating the RTT between the UE and each of the plurality of other nodes, and the timing adjustment parameter for the UE.

[0142] In one aspect, although not illustrated, method 1100 may further include: sending a control signal to the UE, the control signal indicating that the master node and the plurality of other nodes will transmit the plurality of RTT measurement signals during a plurality of predefined symbols of a downlink subframe. The master node may send the control signal on the PDCCH. The control signal may further request the UE to report information indicating the arrival time at the UE of each of the plurality of RTT measurement signals. The UE may include in the payload of the RTT response signal information indicating the arrival time at the UE of each of the plurality of RTT measurement signals. In this case, the reception at 1104 may include: decoding the payload of the RTT response signal. Each of the plurality of other nodes may calculate a respective RTT between the UE and each node based on: (1) the transmission time at each node of the downlink RTT measurement signal among the plurality of other RTT measurement signals transmitted by each node, (2) the information indicating the arrival time at the UE of each of the plurality of RTT measurement signals included in the payload of the RTT response signal, (3) the arrival time of the RTT response signal at each node, (4) the transmission time of the RTT response signal, wherein each node determines the transmission time of the RTT response signal and the information indicating the arrival time at the UE of each of the plurality of RTT measurement signals included in the payload of the RTT response signal by demodulating and decoding the RTT response signal, and wherein the information indicating the RTT between the UE and each node received by the master node from each node includes the calculated respective RTT.

[0143] In one aspect, although not illustrated, method 1100 may further include: sending a timing adjustment parameter to the UE, or receiving a timing adjustment parameter from the UE. The UE may send the RTT response on the PUSCH.

[0144] Figure 12 An exemplary method 1200 for determining a plurality of RTTs at a UE (e.g., UE 102) is illustrated. Method 1000 may be performed by, for example, Figure 3 communication device 308 and / or processing system 334 in based on the execution of RTT measurement component 352.

[0145] At 1202, a UE (e.g., communication device 308) transmits an RTT measurement signal to multiple base stations (e.g., any one of gNBs 502, 622 - 626), where each of the multiple base stations measures the arrival time of the RTT measurement signal relative to the downlink subframe timing of that each base station. In one aspect, the multiple base stations can be neighboring base stations within the communication range of the UE. In one aspect, the UE can transmit the RTT measurement signal on the PUSCH. In one aspect, the RTT measurement signal can be a broadband signal.

[0146] In one aspect, at least one of the multiple base stations receives the RTT measurement signal on each of one or more receive beams of the at least one base station. In one aspect, the at least one base station can utilize multiple receive beams, and wherein, based on the at least one base station having fewer hardware receiver chains than the number of the multiple receive beams, the UE receives a command to transmit the RTT measurement signal multiple times to allow the at least one base station to sequentially cycle through all of the receive beams of the multiple receive beams that can be used by the at least one base station to receive the RTT measurement signal from the UE.

[0147] At 1204, the UE receives an RTT response signal transmitted by each of the multiple base stations. In one aspect, at least one of the multiple base stations can transmit the RTT response signal on each of one or more transmit beams of the at least one base station. In one aspect, the RTT measurement signal and the RTT response signal can be transmitted on low - reuse resources.

[0148] At 1206, the UE obtains the arrival time of the RTT response signal received from each of the multiple base stations at the UE.

[0149] At 1208, the UE obtains information regarding each of the multiple base stations indicating the transmission time of the RTT response signal received from that each base station and the arrival time of the RTT measurement signal measured by that each base station. In one aspect, each of the multiple base stations includes the arrival time of the RTT measurement signal measured by that each base station in the payload of the RTT response signal transmitted by that each base station. In this case, the obtaining at 1208 can include: demodulating and decoding the RTT response signal received from each base station. In one aspect, the obtaining at 1208 can include: receiving the information regarding each of the multiple base stations from the serving base station of the UE.

[0150] At 1208, the UE calculates the RTT between the UE and each of the plurality of base stations based on the transmission time of the signal at the UE measured by the RTT, the arrival time of the RTT response signal received from each of the plurality of base stations at the UE, information indicating the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each of the plurality of base stations, and the timing adjustment parameter for the UE. The UE may receive the timing adjustment parameter from the serving base station of the UE.

[0151] In one aspect, although Figure 12 not illustrated in, method 1200 may further include: receiving a control signal from the serving base station of the UE, the control signal instructing the UE to transmit the RTT measurement signal during a predefined resource block of a subframe. In one aspect, the UE may receive the control signal on the PDCCH.

[0152] In one aspect, although Figure 12 not illustrated in, method 1200 may further include: receiving an instruction from the serving base station of the UE to scan the RTT response signals received from each of the plurality of base stations.

[0153] Figure 13 An example master node device 1300 (e.g., any one of eNBs 202 - 206 or gNBs 502 and 622 - 626) is illustrated as a series of interconnected functional modules represented as being connected by a common bus. The module 1302 for transmission may at least in some aspects correspond to, for example, a communication device (such as Figure 3 the communication device 314 in) and / or a processing system (such as Figure 3 the processing system 334 in) discussed herein. The module 1304 for transmission may at least in some aspects correspond to, for example, a communication device (such as Figure 3 the communication device 314 in) and / or a processing system (such as Figure 3 the processing system 334 in) discussed herein. The module 1306 for reception may at least in some aspects correspond to, for example, a communication device (such as Figure 3 the communication device 314 in) and / or a processing system (such as Figure 3 the processing system 334 in) discussed herein. The module 1308 for calculation may at least in some aspects correspond to, for example, a processing system discussed herein, such as Figure 3 the processing system 334 in.

[0154] Figure 14An example user equipment device 1400, such as UE 102, is illustrated as a series of interrelated functional modules connected by a common bus. The module 1402 for reception may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 308 in Figure 3 ), and / or a processing system (such as the processing system 332 in Figure 3 ) discussed herein. The module 1404 for transmission may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 308 in Figure 3 ), and / or a processing system (such as the processing system 332 in Figure 3 ) discussed herein. The module 1406 for reception may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 308 in Figure 3 ), and / or a processing system (such as the processing system 332 in Figure 3 ) discussed herein. The module 1408 for calculation may correspond, at least in some aspects, to, for example, a processing system (such as the processing system 332 in Figure 3 ), and / or a communication device (such as the communication device 308 in Figure 3 ) discussed herein.

[0155] Figure 15 An example master node device 1500 (e.g., any one of eNBs 202 - 206 or gNBs 502 and 622 - 626) is illustrated as a series of interrelated functional modules connected by a common bus. The module 1502 for transmission may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 314 in Figure 3 ), and / or a processing system (such as the processing system 334 in Figure 3 ) discussed herein. The module 1504 for reception may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 314 in Figure 3 ), and / or a processing system (such as the processing system 334 in Figure 3 ) discussed herein. The module 1506 for reception may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 314 in Figure 3 ), and / or a processing system (such as the processing system 334 in Figure 3 ) discussed herein. The module 1508 for obtaining may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 314 in Figure 3 ), and / or a processing system (such as the processing system 334 in Figure 3 ) discussed herein. The module 1510 for obtaining may correspond, at least in some aspects, to, for example, a communication device (such as the communication device 314 in Figure 3 ), and / or a processing system (such as the processing system 334 in Figure 3The processing system in (334). The module 1512 for receiving may correspond, at least in some aspects, to, for example, a communication device discussed herein (such as Figure 3 the communication device 314 in) and / or a processing system (such as Figure 3 the processing system 334 in). The module 1514 for enabling may correspond, at least in some aspects, to, for example, a communication device discussed herein (such as Figure 3 the communication device 314 in) and / or a processing system (such as Figure 3 the processing system 334 in).

[0156] Figure 16 Illustrated is an example user equipment device 1600, such as UE 102, represented as a series of interconnected functional modules connected by a common bus. The module 1602 for transmitting may correspond, at least in some aspects, to, for example, a communication device discussed herein (such as Figure 3 the communication device 308 in) and / or a processing system (such as Figure 3 the processing system 332 in). The module 1604 for receiving may correspond, at least in some aspects, to, for example, a communication device discussed herein (such as Figure 3 the communication device 308 in) and / or a processing system (such as Figure 3 the processing system 332 in). The module 1606 for obtaining may correspond, at least in some aspects, to, for example, a communication device discussed herein (such as Figure 3 the communication device 308 in) and / or a processing system (such as Figure 3 the processing system 332 in). The module 1608 for obtaining may correspond, at least in some aspects, to, for example, a processing system discussed herein (such as Figure 3 the processing system 332 in) and / or a communication device (such as Figure 3 the communication device 308 in). The module 1610 for calculating may correspond, at least in some aspects, to, for example, a processing system discussed herein (such as Figure 3 the processing system 332 in) and / or a communication device (such as Figure 3 the communication device 308 in).

[0157] Figures 13 - 16The functionality of the modules can be implemented in various ways consistent with the teachings herein. In some designs, the functionality of these modules can be implemented as one or more electrical components. In some designs, the functionality of these blocks can be implemented as a processing system including one or more processor components. In some designs, at least a portion of the functionality of these modules can be implemented using, for example, one or more integrated circuits (e.g., ASICs). As discussed herein, an integrated circuit can include a processor, software, other related components, or some combination thereof. Thus, the functionality of different modules can be implemented, for example, as different subsets of integrated circuits, different subsets of sets of software modules, or combinations thereof. Also, it will be appreciated that a given subset (e.g., of integrated circuits and / or sets of software modules) can provide at least a portion of the functionality of more than one module.

[0158] In addition, Figures 13 - 16 the components and functions represented and the other components and functions described herein can be implemented using any suitable means. Such means can also be implemented at least in part using the corresponding structures taught herein. For example, the components described above in connection with the Figures 13 - 16 "module for..." components can also correspond to similarly named "means for..." functionality. Thus, in some aspects, one or more of such means can be implemented using one or more of the processor components, integrated circuits, or other suitable structures taught herein.

[0159] Those skilled in the art will appreciate that information and signals can 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 referred to throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0160] Furthermore, those skilled in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithmic steps described in connection with the aspects disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above 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.

[0161] 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. The 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.

[0162] 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. The software modules may reside in RAM, flash memory, ROM, EPROM, 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 from, and write 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., a UE). In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

[0163] In one or more exemplary aspects, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. 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. 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, 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. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc where disks typically 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.

[0164] Although the foregoing disclosure shows illustrative aspects of the present disclosure, it should be noted that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims. The functions, steps, and / or acts in the method claims according to aspects of the present disclosure described herein need not be performed in any particular order. Further, although elements of the present disclosure may be described or claimed in the singular, the plural is also contemplated unless expressly stated to be limited to the singular.

Claims

1. A method for determining multiple round-trip times (RTTs) at a user equipment (UE), comprising: Transmitting RTT measurement signals to multiple base stations; Receiving, from each of the multiple base stations, an RTT response signal transmitted by the respective base station; Obtaining the arrival time at the UE of the RTT response signal received from each of the multiple base stations; Obtaining information regarding each of the multiple base stations indicating the transmission time of the RTT response signal received from the respective base station and the arrival time of the RTT measurement signal measured by the respective base station relative to the downlink subframe timing of the respective base station, wherein the arrival time of the RTT measurement signal measured by the respective base station is included in the payload of the RTT response signal transmitted by the respective base station, and wherein obtaining information regarding each of the multiple base stations indicating the transmission time of the RTT response signal received from the respective base station and the arrival time of the RTT measurement signal measured by the respective base station includes: demodulating and decoding the RTT response signal received from the respective base station; And Calculating the RTT between the UE and each of the multiple base stations based on the transmission time of the RTT measurement signal at the UE, the arrival time at the UE of the RTT response signal received from each of the multiple base stations, the information regarding each of the multiple base stations indicating the transmission time of the RTT response signal received from the respective base station and the arrival time of the RTT measurement signal measured by the respective base station, and the timing adjustment parameter for the UE.

2. The method according to claim 1, characterized in that, Further comprising: Receiving a control signal from the serving base station of the UE, the control signal instructing the UE to transmit the RTT measurement signal during a predefined resource block of a subframe.

3. The method according to claim 2, wherein The UE receives the control signal on a physical downlink control channel (PDCCH).

4. The method according to claim 1, wherein Further comprising: Receiving an instruction from the serving base station of the UE to scan the RTT response signals received from each of the multiple base stations.

5. The method according to claim 1, characterized in that The UE receives the timing adjustment parameter from the serving base station of the UE.

6. The method according to claim 1, wherein The UE transmits the RTT measurement signal on a physical uplink shared channel (PUSCH).

7. The method according to claim 1, wherein The multiple base stations include neighboring base stations within the communication range of the UE.

8. The method according to claim 1, wherein The RTT measurement signal includes a broadband signal.

9. The method according to claim 1, characterized in that At least one of the multiple base stations transmits the RTT response signal on each of one or more transmit beams of the at least one base station.

10. The method according to claim 1, characterized in that, At least one of the multiple base stations receives the RTT measurement signal on each of one or more receive beams of the at least one base station.

11. The method according to claim 10, wherein The at least one base station utilizes a plurality of receive beams, and wherein, based on the at least one base station having fewer hardware receiver chains than the number of the plurality of receive beams, the UE receives an order to transmit the RTT measurement signal multiple times to allow the at least one base station to sequentially cycle through all of the plurality of receive beams that can be used by the at least one base station to receive the RTT measurement signal from the UE.

12. The method according to claim 1, wherein The RTT measurement signal and the RTT response signal are transmitted on low-reuse resources.

13. The method according to claim 1, characterized in that, Obtaining information indicating a transmission time of the RTT response signal received from each of the plurality of base stations and an arrival time of the RTT measurement signal measured by each of the plurality of base stations includes: receiving, from a serving base station of the UE, the information regarding each of the plurality of base stations.

14. An apparatus for determining a plurality of round-trip times (RTTs) at a user equipment (UE), comprising: a transceiver of the UE, configured to: transmit an RTT measurement signal to a plurality of base stations; and receive an RTT response signal transmitted by each of the plurality of base stations from each of the plurality of base stations; and at least one processor of the UE, configured to: obtain an arrival time of the RTT response signal received from each of the plurality of base stations at the UE; obtain information indicating a transmission time of the RTT response signal received from each of the plurality of base stations and an arrival time of the RTT measurement signal measured by each of the plurality of base stations relative to a downlink subframe timing of each of the plurality of base stations, wherein the arrival time of the RTT measurement signal measured by each of the plurality of base stations is included in a payload of the RTT response signal transmitted by each of the plurality of base stations, and wherein obtaining information indicating a transmission time of the RTT response signal received from each of the plurality of base stations and an arrival time of the RTT measurement signal measured by each of the plurality of base stations includes: demodulating and decoding the RTT response signal received from each of the plurality of base stations; and calculate an RTT between the UE and each of the plurality of base stations based on a transmission time of the RTT measurement signal at the UE, an arrival time of the RTT response signal received from each of the plurality of base stations at the UE, information indicating a transmission time of the RTT response signal received from each of the plurality of base stations and an arrival time of the RTT measurement signal measured by each of the plurality of base stations, and a timing adjustment parameter for the UE.

15. The device according to claim 14, characterized in that, The transceiver is further configured to: receive a control signal from a serving base station of the UE, the control signal instructing the UE to transmit the RTT measurement signal during a predefined resource block of a subframe.

16. The device according to claim 15, characterized in that The transceiver receives the control signal on a physical downlink control channel (PDCCH).

17. The device according to claim 14, characterized in that, The transceiver is further configured to: receive from the serving base station of the UE an instruction to scan the RTT response signals received from each of the plurality of base stations.

18. The device according to claim 14, characterized in that, The UE receives the timing adjustment parameter from the serving base station of the UE.

19. The device according to claim 14, wherein The UE transmits the RTT measurement signal on a Physical Uplink Shared Channel (PUSCH).

20. The device according to claim 14, characterized in that, The plurality of base stations are neighboring base stations within the communication range of the UE.

21. The device according to claim 14, wherein, The RTT measurement signal includes a broadband signal.

22. The device according to claim 14, characterized in that, At least one base station of the plurality of base stations transmits the RTT response signal on each of one or more transmit beams of the at least one base station.

23. The device according to claim 14, characterized in that, At least one base station of the plurality of base stations receives the RTT measurement signal on each of one or more receive beams of the at least one base station.

24. The device according to claim 23, characterized in that, The at least one base station utilizes a plurality of receive beams, and wherein, based on the at least one base station having fewer hardware receiver chains than the number of the plurality of receive beams, the UE receives an order to transmit the RTT measurement signal multiple times to allow the at least one base station to sequentially cycle through all of the plurality of receive beams that can be used by the at least one base station to receive the RTT measurement signal from the UE.

25. The device according to claim 14, wherein, The RTT measurement signal and the RTT response signal are transmitted on low-reuse resources.

26. The device according to claim 14, wherein The at least one processor is configured to obtain the information regarding the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each base station, including: the at least one processor is configured to receive, via the transceiver, from the serving base station of the UE the information regarding each of the plurality of base stations.

27. A device for determining multiple round-trip times (RTTs) at a user equipment (UE), comprising: A communication device of the UE, which is configured to: Transmit an RTT measurement signal to a plurality of base stations; And Receive, from each of the plurality of base stations, an RTT response signal transmitted by each of the plurality of base stations; And A processing device of the UE, which is configured to: Obtain the arrival time at the UE of the RTT response signal received from each of the plurality of base stations; Obtain information indicating the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each base station relative to the downlink subframe timing of each base station, wherein the arrival time of the RTT measurement signal measured by each base station is included in the payload of the RTT response signal transmitted by each base station, and wherein obtaining information indicating the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each base station includes: demodulating and decoding the RTT response signal received from each base station; and Calculate the RTT between the UE and each of the plurality of base stations based on the transmission time of the RTT measurement signal at the UE, the arrival time of the RTT response signal received from each of the plurality of base stations at the UE, the information indicating the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each base station, and the timing adjustment parameter for the UE.

28. The apparatus according to claim 27, further comprising means for performing the method according to any one of claims 2 to 13.

29. A non-transitory computer-readable medium storing computer-executable instructions for determining a plurality of round-trip times (RTTs) at a user equipment (UE), the computer-executable instructions comprising: At least one instruction for causing the UE to transmit an RTT measurement signal to a plurality of base stations; At least one instruction for causing the UE to receive an RTT response signal transmitted by each of the plurality of base stations from each of the plurality of base stations; At least one instruction for causing the UE to obtain the arrival time of the RTT response signal received from each of the plurality of base stations at the UE; At least one instruction for causing the UE to obtain information indicating the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each base station relative to the downlink subframe timing of each base station, wherein the arrival time of the RTT measurement signal measured by each base station is included in the payload of the RTT response signal transmitted by each base station, and wherein obtaining information indicating the transmission time of the RTT response signal received from each of the plurality of base stations and the arrival time of the RTT measurement signal measured by each base station includes: demodulating and decoding the RTT response signal received from each base station; and At least one instruction for the UE to calculate the round-trip time (RTT) between the UE and each of the plurality of base stations based on the transmission time of the RTT measurement signal at the UE, the arrival time of the RTT response signal received from each base station in the plurality of base stations at the UE, information regarding the transmission time of the RTT response signal indicated for each base station in the plurality of base stations and received from each base station, and the arrival time of the RTT measurement signal measured by each base station, and timing adjustment parameters for the UE.

30. The non-transitory computer-readable medium of claim 29, further comprising computer-executable instructions that cause the UE to perform the method of any one of claims 2 to 13.

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