System and method for multiple round trip time (RTT) estimation in wireless networks

Abstract

The present application relates to systems and methods for multiple round trip time (RTT) estimation in wireless networks. A technique for determining the round trip time (RTT) between a user equipment (UE) and multiple base stations is disclosed. On the one hand, 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. On the other hand, these base stations each transmit 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 separate messages. These RTT signals may be broadband signals using low reuse resources.

Description

[0001] This application is a divisional application of a patent application with application number 201880081243.9, application date December 18, 2018, and invention name “System and method for multi-round trip time (RTT) estimation in wireless networks”.

[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 the present application and is expressly incorporated herein by reference in its entirety.

[0004] Public background

[0005] 1. Public Domain

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

[0007] 2. Description of related technologies

[0008] Wireless communication systems have evolved over several generations, including first generation analog wireless telephone service (1G), second generation (2G) digital wireless telephone service (including transitional 2.5G networks), third generation (3G) high-speed data wireless service with Internet capabilities, and fourth generation (4G) services (e.g., LTE or WiMax). There are many different types of wireless communication systems in use today, including cellular and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), global system for mobile access (GSM) TDMA variants, and the like.

[0009] The fifth generation (5G) wireless standard enables higher data transmission speeds, a greater number of connections and better coverage, among other improvements. According to the Next Generation Mobile Network Alliance, the 5G standard is designed to provide tens of megabits per second data rates to each of tens of thousands of users, and 1 gigabit per second data rate to dozens of employees in an office building. Hundreds of simultaneous connections should be supported to support large wireless sensor deployments. Therefore, the spectrum efficiency of 5G mobile communications should be significantly improved compared to the current 4G standard. In addition, signaling efficiency should be improved and waiting time should be significantly reduced compared to the current standard.

[0010] Overview

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

[0012] In one aspect, a method performed by a master node for determining a plurality of round trip times (RTTs) for a user equipment (UE) includes: sending 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 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;

[0013] Receive an RTT response signal from the UE, obtain the arrival time of the RTT response signal at the master node, obtain the transmission time of the RTT response signal, receive information indicating the RTT between the UE and each of the multiple other nodes from the multiple other nodes, and determine 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 the following: the transmission time of the RTT measurement signal at the master node, information indicating the arrival time of each RTT measurement signal in the multiple RTT measurement signals arriving 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 multiple other nodes, and timing adjustment parameters for the UE.

[0014] In one aspect, a method for determining multiple RTTs at a UE includes: transmitting an RTT measurement signal to multiple base stations, wherein each of the multiple base stations measures an arrival time of the RTT measurement signal relative to a downlink subframe timing of the each base station, receiving an RTT response signal transmitted by each of the multiple base stations from each of the multiple base stations, obtaining an arrival time of the RTT response signal received from each of the multiple base stations at the UE, obtaining information about each of the multiple base stations indicating a transmission time of the RTT response signal received from each of the multiple base stations and an arrival time of the RTT measurement signal measured by each 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 of the RTT response signal received from each of the multiple base stations at the UE, the information about each of the multiple base stations indicating a transmission time of the RTT response signal received from each of the multiple base stations 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: send an RTT measurement signal to the UE on a cellular cell supported by the master node during one or more predefined code elements of a downlink subframe, receive from the UE information indicating an arrival time of each of the multiple RTT measurement signals at the UE, wherein the multiple RTT measurement signals include the RTT measurement signal and multiple other RTT measurement signals transmitted by multiple 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 The device is further configured to: receive information indicating the RTT between the UE and each of the multiple other nodes from the multiple other nodes, and wherein the at least one processor is further configured to: determine 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 the following items: the transmission time of the RTT measurement signal at the master node, information indicating the arrival time of each of the multiple 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 multiple other nodes, and a timing adjustment parameter for the UE.

[0016] In one aspect, an apparatus for determining multiple RTTs at a UE includes: a transceiver of the UE, configured to: transmit an RTT measurement signal to a plurality of base stations, wherein each 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 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 an indication of each of the plurality of base stations from each of the plurality of base stations, and The method comprises: 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 of the RTT response signal received from each of the multiple base stations at the UE, the transmission time of the RTT response signal received from each of the multiple base stations 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 RTTs for a UE comprises: a communication device of a master node, configured to: send an RTT measurement signal to the UE on a cellular cell supported by the master node during one or more predefined code elements of a downlink subframe, receive from the UE 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 include the RTT measurement signal and a plurality of other RTT measurement signals transmitted by a plurality of other nodes, receive from the UE an RTT response signal; and a processing device 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 The device is further configured to: receive information indicating the RTT between the UE and each of the multiple other nodes from the multiple other nodes, and wherein the processing device is further configured to: determine 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 the following items: the transmission time of the RTT measurement signal at the master node, information indicating the arrival time of each of the multiple 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 multiple other nodes, and a timing adjustment parameter for the UE.

[0018] In one aspect, an apparatus for determining multiple RTTs at a UE comprises: a communication device of the UE, configured to: transmit an RTT measurement signal to a plurality of base stations, wherein each 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 receives an RTT response signal transmitted by each of the plurality of base stations from each 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 of the plurality of base stations at the UE, obtain an indication of each of the plurality of base stations from each of the plurality of base stations The RTT between the UE and each of the multiple base stations is calculated 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 multiple base stations at the UE, the information about each of the multiple 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 RTTs for a UE includes computer-executable instructions, which include: at least one instruction to instruct a master node to send an RTT measurement signal to the UE on a cellular cell supported by the master node during one or more predefined code elements 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 arriving at the UE, wherein 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, and at least one instruction to instruct the master node to obtain at least one indication of the arrival time of the RTT response signal arriving at the master node. The invention relates to a method for controlling the master node to determine 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 the following items: the transmission time of the RTT measurement signal at the master node, the information indicating the arrival time of each RTT measurement signal in the multiple 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 the RTT between the UE and each of the multiple other nodes, and the timing adjustment parameters for the UE.

[0020] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions for determining multiple RTTs at a UE includes computer-executable instructions, the computer-executable instructions including: at least one instruction to instruct the UE to transmit an RTT measurement signal to a plurality of base stations, wherein each 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, at least one instruction to instruct the UE to receive an RTT response signal transmitted by each of the plurality of base stations, at least one instruction to instruct the UE to obtain an arrival time of the RTT response signal received from each of the plurality of base stations to the UE, and at least one instruction to instruct the UE to obtain information about the plurality of base stations. at least one instruction for instructing the UE to calculate 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 of the RTT response signal received from each of the multiple base stations at the UE, the information about each of the multiple 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.

[0021] Other objects and advantages associated with the various aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are presented to aid in describing various aspects of the disclosure and are provided solely for the purpose of illustrating these aspects and not limiting thereof.

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

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

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

[0026] Figure 3 is a simplified block diagram of several sample aspects of components that may be employed in a wireless communication node and configured to support communications 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 illustrating exemplary timing within an RTT procedure that occurs during wireless probe requests and responses.

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

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

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

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

[0033] Fig.13 16 is another simplified block diagram of several sample aspects of an apparatus 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). In addition, some elements in 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 the numerical prefix. For example, Figure 1A Different instances of UE 102-1, 102-2, 102-3, 102-4, 102-5, and 102-N are shown in FIG. 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 In the present invention, any reference to RAN 120 may refer to Figure 1A RAN 120A or RAN 120B in. Detailed Description

[0035] Various aspects of the present disclosure are provided in the following description and related drawings for various examples provided for illustrative purposes. Alternative aspects may be designed without departing from the scope of the present disclosure. In addition, well-known elements in the present disclosure will not be described in detail or will be omitted to avoid obscuring the relevant details of the present disclosure.

[0036] The words "exemplary" and / or "example" are used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" and / or "example" is not necessarily to be construed as preferred or superior to other aspects. Likewise, the term "aspects of the disclosure" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation.

[0037] Those skilled in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the following description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, etc.

[0038] In addition, many aspects are described in the form of a sequence of actions performed by, for example, elements of a computing device. It will be appreciated that the various actions described herein can be performed by a dedicated circuit (e.g., an application specific integrated circuit (ASIC)), by program instructions being executed by one or more processors, or by a combination of the two. In addition, the sequence of actions described herein may be considered to be fully embodied in any form of non-transient computer-readable storage medium, which stores a corresponding set of computer instructions that, upon execution, will cause or instruct the associated processor of the device to perform the functionality described herein. Thus, various aspects of the present disclosure may be implemented in several different forms, all of which have been conceived to fall within the scope of the subject matter claimed for protection. In addition, for each aspect described herein, the corresponding form of any such aspect may 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 may be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, a tracking device, an Internet of Things (IoT) device, etc.) used by a user to communicate on a wireless communication network. A UE may be mobile or may be stationary (e.g., at certain times) and may communicate with a radio access network (RAN). As used herein, the term "UE" may be interchangeably referred to as an "access terminal" or "AT," "client device," "wireless device," "subscriber equipment," "subscriber terminal," "subscriber station," "user terminal" or UT, "mobile terminal," "mobile station," or variations thereof. In general, UEs are able to communicate with a core network via a RAN, and through the core network, these UEs are able to connect to external networks (such as the Internet) and to other UEs. Of course, other mechanisms for connecting to a core network and / or the Internet are also possible for a UE, such as through a wired access network, a WiFi network (e.g., based on IEEE 802.11, etc.), and the like.

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

[0041] Figure 1A A high-level system architecture of a wireless communication system 100 according to one aspect of the present disclosure is illustrated. The wireless communication system 100 includes UEs 1 to N (referenced as 102-1 to 102-N). The UEs 102-1 to 102-N may include cellular phones, personal digital assistants (PDAs), pagers, laptop computers, tablet computers, desktop computers, etc. For example, in Figure 1A1, 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 touch screen phones or "smart phones," and UE 102-N is illustrated as a desktop computer or personal computer (commonly referred to as a "PC"). Figure 1A Only six UEs 102 are shown in FIG. 1 , but the number of UEs 102 in the wireless communication system 100 may be hundreds, thousands, or millions (eg, N may be any number up to one million or more).

[0042] Reference Figure 1A , UEs 102-1 to 102-N are configured to communicate at a physical communication interface or layer (at Figure 1A 104, 106, and 108) and / or direct wired connections with one or more access networks (e.g., RAN 120A and 120B, access point 125, etc.). The air interfaces 104 and 106 may comply with a given cellular communication protocol (e.g., code division multiple access (CDMA), evolution data optimization (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), fifth generation (5G) new radio (NR), etc.), while the air interface 108 may comply with a wireless local area network (WLAN) protocol (e.g., IEEE 802.11). Both RAN 120A and 120B may include multiple access points that serve UEs through air interfaces (such as air interfaces 104 and 106). The access points in the RAN 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 generally a base station that supports wireless access by UE 102 according to an LTE wireless interface defined by the Third Generation Partnership Project (3GPP). As another example, a g B node or gNB is generally a base station that supports wireless access by UE 102 according to a 5G NR wireless 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 a core network 140, which may perform a variety of functions including routing and connecting circuit-switched (CS) calls between a UE 102 served by the RAN 120A / 120B and other UEs 102 served by the RAN 120A / 120B or by a different RAN, and may 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 here for convenience). Figure 1A ). Figure 1A 1, UE 102-N is shown as being directly connected to Internet 175 (i.e., separate from core network 140, such as via an Ethernet connection based on WiFi or IEEE 802.11 networks). 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 core network 140.

[0045] Figure 1A 1 and 120B. The access point 125 is also shown as being separate from the RANs 120A and 120B. The access point 125 may 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 may serve the UE 102-4 or UE 102-5 via a local wireless connection (such as IEEE 802.11 in one example). The UE 102-N is shown as a desktop computer with a wired connection to the Internet 175 (such as a direct connection to a modem or router), which in one example may correspond to the access point 125 itself (e.g., for a WiFi router with both wired and wireless connectivity).

[0046] Reference Figure 1A , location server 170 is shown connected to Internet 175 and core network 140. Location server 170 may be implemented as a plurality of structurally separate servers, or alternatively may correspond to a single server. As will be described in more detail below, location server 170 is configured to support one or more location services for UE 102, which may be connected to location server 170 via core network 140 and / or Internet 175. When supporting the location of UE 102 with 5G NR wireless access (e.g., where core network 140 is or includes a 5G core network), location server 170 may correspond to a location management function (LMF).

[0047] Below about Figure 1BAn example of a protocol-specific implementation of the RANs 120A and 120B and the core network 140 is provided to help explain the wireless communication system 100 in more detail. In particular, the components of the RANs 120A and 120B and the core network 140 correspond to components associated with supporting packet-switched (PS) communications, where legacy circuit-switched (CS) components may also be present in these networks, but not in the RANs 120A and 120B. Figure 1B Any legacy CS-specific components are explicitly shown in .

[0048] Figure 1B An example configuration of a portion of the RAN 120A and a portion of the 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. Figure 1B , the RAN 120A is configured with multiple eNBs 202, 204, and 206. Figure 1B In the example of FIG. 1 , the eNB 202 is shown as a home eNB (HeNB) and interfaces with the RAN 120A via the HeNB gateway 245. The 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, other APs with smaller coverage areas, and the like. Small cells may be deployed to supplement macrocell (e.g., eNB) coverage and / or increase network capacity. Small cells may provide wireless coverage indoors (such as in a house, office, part of a larger building, part of a conference center, shopping mall, etc.). Small cells may alternatively or additionally provide wireless coverage outdoors (such as in an area covering a block or a portion of several blocks within a neighborhood). Relative to macrocells (which typically use licensed frequency bands for communication), small cells may use unlicensed frequency bands for communication.

[0049] exist Figure 1B , the 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 the E-SMLC 225 may include obtaining location measurements for the UE 102 (e.g., from the UE 102 and / or from the RAN 120), calculating the location of the UE 102, and / or providing assistance data to the UE 102 to enable the UE 102 to obtain location measurements and / or calculate a location estimate. Figure 1B In 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 definitions

[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 a gateway that terminates the SGi interface towards a packet data network (PDN), such as the Internet 175. If the UE 102 is accessing multiple PDNs, there may be more than one P-GW 235 for the UE 102. P-GW 235 functions include providing PDN connectivity to the UE 102, UE IP address allocation, setting 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] like Figure 1B As further explained in FIG. 1 , external client 250 may be connected to core network 140 via GMLC 220 and / or SLP 240. External client 250 may optionally be connected to core network 140 and / or SLP 260 via Internet 175. External client 250 may be a server, a web server, or a user device such as a personal computer, UE, etc.

[0059] Figure 1B The HeNB Gateway 245 in the embodiment may be used to support the connection of small cells and / or HeNBs (such as HeNB 202). The HeNB Gateway 245 may include or be connected to a security gateway ( Figure 1B 202). The security gateway may help authenticate small cells and / or HeNBs (such as HeNB 202), and / or may enable secure communications between small cells and / or HeNBs (such as HeNB 202) and other network entities (such as MME 215). HeNB gateway 245 may perform protocol relaying and translation to allow small cells and / or HeNBs (such as HeNB 202) to communicate with other entities (such as MME 215).

[0060] GMLC 220 may be a location server that enables external clients, such as external client 250, to request and obtain a location estimate for UE 102. Functions of GMLC 220 may include authenticating and authorizing external client 250, and requesting and obtaining a location estimate for UE 102 from MME 215 on behalf of external client 250.

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

[0062] The network for providing 5G NR wireless access to UE 102 may be similar to that described above for Figure 1B The example wireless communication system 100 described above may also have certain differences. Specifically, in a 5G network: eNBs 204 and 206 and HeNB 202 may each be replaced by a gNB that provides NR wireless access to UE 102; HeNB gateway 245 may not exist; MME 215 may be replaced by an access and mobility management function (AMF) connected to these gNBs and a session management function (SMF) connected to the AMF, the AMF and the SMF together performing functions similar to those performed by MME 215; both S-GW 230 and P-GW 235 may be replaced by a user plane function (UPF), the UPF performing functions similar to those performed by both S-GW 230 and P-GW 235; E-SMLC 225 may be replaced by an LMF, the LMF performing functions similar to or identical to those performed by E-SMLC 225; and GMLC 220 may be retained and continue to perform functions similar to or identical to those previously described. Different 5G core functionalities (for example, location management functions, access and mobility functions, security anchor functions, session management functions, authentication server functions, etc.) can be implemented in a distributed manner to a certain extent, with some functionalities performed by the same network equipment and some functionalities performed by different network equipment; and can be implemented in different network equipment (compared with the implementation of similar functions in the 4G core network).

[0063] The time intervals of communication resources in LTE or 5G NR may 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 illustrated. However, as will be readily appreciated by those skilled in the art, the frame structure for any particular application may differ 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 two time slots 205, each time slot 205 including a resource block 207. The resource grid is divided into multiple resource elements. In LTE, and in some cases in 5G NR, a resource block includes 12 consecutive subcarriers 209 in the frequency domain, and for a normal cyclic prefix in each OFDM symbol 211, 7 consecutive OFDM symbols 211 in the time domain, or 84 resource elements. Some resource elements such as those indicated as R0 and R1 include downlink reference signals (DL-RS). DL-RS includes RS (CRS) (sometimes also called common RS) that varies from cell to cell and RS (UE-RS) that varies from UE to UE. UE-RS is transmitted only on the resource block 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 a 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 modulation, frequency slots, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain for OFDM and in the time domain for SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of the subcarriers can be 15kHz, and the minimum resource allocation (resource block) can be 12 subcarriers (or 180kHz). Therefore, for system bandwidths 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 may cover 1.08 MHz (ie, 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0066] Figure 3Several example components (represented by corresponding blocks) that may be incorporated into apparatus 302, apparatus 304, and apparatus 306 (e.g., corresponding to, for example, a UE, a base station (e.g., a gNB), and a network entity or location server, respectively) to support operations as taught herein are illustrated. As an example, apparatus 302 may correspond to UE 102, apparatus 304 may correspond to any of eNB 202-206 or gNB, 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-chip (SoC), etc.) in different implementations. The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in the system may include components similar to those described to provide similar functionality. In addition, a given apparatus may include one or more of these components. For example, a device may include multiple transceiver components that enable the device to operate on multiple carriers and / or communicate via different technologies.

[0067] Each of the 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 designated 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] The transmitter and receiver may comprise an integrated device (e.g., a transmitter circuit and a receiver circuit implemented as a single communication device) in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be implemented in other ways in other implementations. In one aspect, the transmitter may comprise multiple antennas, such as an antenna array, which permits the corresponding device to perform transmit "beamforming", as further described herein. Similarly, the receiver may comprise 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 so that the corresponding device can only receive or transmit at a given time, but not both at the same time. The wireless communication device (e.g., one of the multiple wireless communication devices) of the device 304 may also include a network listening module (NLM) for performing various measurements, etc.

[0069] Devices 304 and 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 In the example of , the communication device 326 is shown as including a transmitter 328 and a receiver 330 (e.g., a network access port for transmitting and receiving). Similarly, the communication device 320 may include a network interface configured to communicate with one or more network entities via a wire-based backhaul or a wireless backhaul. Like the communication device 326, the communication device 320 is shown as including a transmitter 322 and a receiver 324.

[0070] The devices 302, 304, and 306 also include other components that can be used in conjunction with the operations disclosed herein. The device 302 includes a processing system 332 for providing functionality related to RTT measurements in licensed or unlicensed frequency bands, such as disclosed herein, and for providing other processing functionality. The device 304 includes a processing system 334 for providing functionality related to RTT measurements in licensed or unlicensed frequency bands, such as disclosed herein, and for providing other processing functionality. The device 306 includes a processing system 336 for providing functionality related to RTT measurements in licensed or unlicensed frequency bands, such as disclosed herein, and for providing other processing functionality. In one aspect, the processing systems 332, 334, and 336 may 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 circuit systems.

[0071] The devices 302, 304, and 306 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.). In addition, the devices 302, 304, and 306 include user interface devices 344, 346, and 348, respectively, for providing indications to a user (e.g., audible and / or visual indications) and / or for receiving user input (e.g., when a user actuates a sensing device (such as a keypad, a touch screen, a microphone, etc.)

[0072] For convenience, devices 302, 304 and 306 are shown in Figure 3 1 and 2. The illustrated example is shown as including various components that may be configured according to the various examples described herein. However, it will be appreciated that the illustrated blocks may have different functionality in different designs.

[0073] Figure 3 The components of can be implemented in various ways. In some implementations, Figure 3The components of may be implemented in one or more circuits, such as, for example, one or more processors and / or one or more ASICs (which may include one or more processors). Here, each circuit may use and / or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks 308, 332, 338, and 344 may be implemented by the processor and (or) 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 (or) memory components of device 304 (e.g., by executing appropriate code and / or by appropriately configuring the processor components). In addition, some or all of the functionality represented by blocks 326, 336, 342, and 348 may be implemented by the processor and (or) memory components of device 306 (e.g., by executing appropriate code and / or by appropriately configuring the processor components).

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

[0075] As a specific example, 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, devices 302 and 304 may operate via 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 (e.g., LTE networks, 5G NR networks, etc.), TDMA networks, FDMA networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, etc. Although various licensed frequency bands have been reserved for wireless communications (e.g., by government entities such as the Federal Communications Commission (FCC) in the United States), certain communications networks (particularly those that employ small cell base stations) have expanded operations into unlicensed frequency bands, such as the Unlicensed National Information Infrastructure (U-NII) band used by WLAN technologies (most notably the IEEE 802.11x WLAN technology generally referred to as “Wi-Fi”), and LTE in unlicensed spectrum technology generally referred to as “LTE-U” or “MuLTEFire”.

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

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

[0078] Figure 4A simplified environment for illustrating an exemplary technique for determining the location of a UE 102 is shown in FIG. UE 102 may wirelessly communicate with multiple eNBs 202-206 using radio frequency (RF) signals and standardized protocols for modulation of the RF signals and exchange of information packets. By extracting different types of information from the exchanged signals and utilizing the layout of the network (i.e., the network geometry design), UE 102 may determine its location in a predefined reference coordinate system. Figure 4 As shown in , UE 102 may use a two-dimensional coordinate system to specify its position (x, y); however, the aspects disclosed herein are not limited thereto and may also be adapted to use a three-dimensional coordinate system to determine position when additional dimensions are desired. Figure 4 Three eNBs 202-206 are shown, but aspects may utilize additional eNBs.

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

[0080] UE 102 may then determine the distance (d k , where k=1, 2, 3). As will be described in more detail below, there are methods for estimating these distances (d ) by exploiting different characteristics of the RF signals exchanged between UE 102 and eNBs 202-206. k Such characteristics may 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, these distances (d k ). For example, other positioning systems (such as GPS) may be used to provide k (Note that GPS will likely have insufficient signal strength in the expected operating environment (indoors, urban areas, etc.) to provide a rough estimate of d kHowever, GPS signals may be combined with other information to assist in the position determination process. Other relative positioning devices (e.g., onboard accelerometers) that may be used as a basis for providing a rough estimate of relative position and / or direction may 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. Figure 4 From the above, it can be seen that the location of UE 102 is ideally located at the common intersection of all circles drawn using dashed lines. Each circle has a radius d k and 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 be at a single point.

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

[0084] exist Figure 4 In a variation of the technique shown in , each of the eNBs 202-206 may be replaced by a gNB. In this variation, the principles of the technique may remain as previously described, with the UE 102 located at the common intersection of the circles, and with each circle centered at one of the gNBs and having a radius obtained from the measurement of the RTT between the UE 102 and the gNB.

[0085] In some instances (e.g., as described later in Figure 8 As described), additional information in the form of an angle of arrival (AOA) or an angle of departure (AOD) may be obtained, where the AOA or AOD defines a straight-line direction (e.g., the straight-line direction may be in a horizontal plane, or in three-dimensional space) or a possible range of directions (e.g., the range of directions of UE 102 from the location of the gNB or eNB). Figure 44 and 5. Two such exemplary straight-line directions 402 and 404 from eNBs 202 and 206, respectively, are illustrated in FIG. The intersection of these two directions 402 and 404 at point 406 may 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 the eNB or gNB or around another eNB or gNB may provide another estimate of the location of UE 102. For example, Figure 4 Point 408 in illustrative embodiment illustrates the intersection of direction 402 with a circle (or sphere) around eNB 202. The position estimate provided by the direction from the gNB or eNB may be further combined with the position estimate provided by the RTT to improve the position estimate for UE 102, as is known in the art.

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

[0087] Figure 5A 5 is a diagram 500 showing exemplary timing within an RTT measurement that occurs during a wireless probe request and response. In one aspect, the response may take the form of an acknowledgment packet (ACK); however, any type of response packet will be consistent with various aspects of the present disclosure. For example, a request to send (RTS) transmit packet and / or a clear to send (CTS) response packet may be suitable. Figure 5A Illustrated as using gNB 502, but any of eNBs 202-206 may be substituted Figure 5A The gNB 502 in the measurement will not change the measurement procedure.

[0088] To measure the RTT for a given gNB 502, UE 102 may send a directional probe request (PR) packet to the gNB 502 and record the time it takes to send the probe request packet (“t TX Group")), such as Figure 5A The transmission time t of the probe request packet between UE 102 and gNB 502 is shown in FIG. PAfterwards, the gNB 502 will receive the packet (assuming line of sight (LOS) propagation). The gNB 502 may then process the directional probe request packet and may send an ACK back to the UE 102 after some processing time Δ, as shown in FIG. Figure 5A At the second propagation time t p Afterwards, UE 102 may record the receipt of the ACK packet (“t RX ACK”) as shown on the UE 102 timeline. The UE 102 can then determine the RTT as the time difference t RX ACK-t TX However, the RTT obtained in this manner may include an error component due to the processing time Δ, which may not always be accurately known. The distance D between UE 102 and gNB 502 may be obtained as (RTT / c), where c is the radio signal propagation speed (usually the speed of light). The distance D may then be used to determine the area around gNB 502 on which UE 102 may be located (e.g., Figure 4 a circle or sphere.

[0089] Positioning methods currently used in cellular networks, such as Observed Time Difference of Arrival (OTDOA), typically require fine (e.g., sub-microsecond) timing synchronization across 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). The present disclosure describes procedures that can be implemented in 5G NR networks that take advantage of 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, it is sufficient to have (coarse) CP-level time synchronization across gNBs. Coarse time synchronization enables 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, therefore, more accurate positioning.

[0091] In network-centric RTT estimation, a serving gNB instructs a 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 RTT measurement signals on low reuse resources (i.e., resources used by base stations 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, reception time, reception time, or arrival time) of each RTT measurement signal relative to the current downlink timing of the UE (e.g., derived by the UE from DL signals 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 RTT response message(s).

[0092] UE-centric RTT estimation is similar to the network-based approach, except that a UE (e.g., UE 102) transmits uplink RTT measurement signal(s) (e.g., when instructed by a 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 network-centric and UE-centric procedures, the side performing the RTT calculation (the network or the UE) typically (but not always) transmits first message or signal(s) (e.g., RTT measurement signal(s)), 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 is a diagram 550 showing exemplary timing within an RTT measurement that occurs during a wireless probe request and response, where the RTT calculation may be compared to Figure 5A The RTT calculation in is more accurate. 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. Figure 5B550 , 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, while 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 timing 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 known as a "timing advance" or "timing adjustment" (often abbreviated as TA) so 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, a 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 is assumed to be earlier than the timing at E1 552 by an amount δ (but may lag behind the timing at E1 552 if δ is negative). This assumption allows for both synchronous networks (e.g., where δ may be zero) and unsynchronized or asynchronous networks (where δ may 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), which 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), which is received at time Rx1 at E1 552 (and thus at time Rx1+δ at E2 554). The equations below diagram 550 assume that compensation for any TA 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 in any 5G network), it is possible to measure the transmission time and arrival time relative to the 1ms NR subframe timing by using values ​​modulo 1ms. This can simplify the measurement because integer multiples of 1ms do not need to be measured, recorded, or transmitted.

[0096] Figure 5B The entity E1 552 in (or some other entity to which E1 552 forwards its measurements) may use the measured Tx0 and Rx1 values ​​and the Rx0 and Tx1 values, according to Figure 5B570 in . The values ​​of Rx0 and Tx1 may be obtained by E1 552 according to one of four alternative variants (labeled here as 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. Entity E1 552 may then determine the RTT from the known Rx0, Rx1, Tx0, and Tx1 values ​​(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 entities E1 552 and E2 554 are far from each other (e.g., for a UE 5 km or more 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, where variants V2, V3, and V4 (described below) are utilized, E1 552 may not always need to demodulate and decode the RTT response 564 (e.g., may only need to demodulate the RTT response 564 sufficiently to measure the arrival time Rx1), which may enable measurement of weaker signals and / or interfered signals.

[0097] In the case of utilizing 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 may further send or receive Rx0 and Tx1 values ​​(or values ​​indicating Rx0 and Tx1) to or from the gNB for which the RTT is to be obtained when the gNB is not the serving gNB, respectively. Although variant V2 ensures the correct transmission of Rx0 and Tx1, the additional separate message may both add additional delay and require more signaling.

[0098] In the case of utilizing variant V3 (which is applicable only when E2 554 is a UE), the UE includes the measurement Rx0 in the payload of the RTT response 564, and the serving gNB of the UE (but not other gNBs) demodulates and decodes the RTT response 564 to obtain the Rx0 measurement and measures Tx1. The serving gNB may then forward the Rx0 and Tx1 values ​​to the gNB for which the RTT is being measured, if necessary.

[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 may be performed at the non-serving gNB only when variant V1 is used. 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 UE's serving gNB, or a location server), which may then calculate the RTT or may transmit the information to another entity (e.g., a location server) where RTT calculation may occur. The entity performing the RTT calculation (or receiving the calculated RTT) may further obtain the UE's location—e.g., as described for Figure 4 as described.

[0102] In order to compensate for the TA value (in Figure 5B 564), when E1 552 is a UE, the UE may simply subtract this 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 variant V1 or variant V3 is used, the transmission time Tx1 determined by E1 552 will be wrong and will exceed the correct value of Tx1 by the amount TA. To compensate, the UE may 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 may send a TA value to the serving gNB (in the event that the serving gNB does not have a TA value), and the network side may adjust Tx1 by subtracting this TA value. All of these additions and subtractions may be performed modulo 1ms.

[0103] Figure 6 and Figure 7 Additional examples are provided to determine the RTT when the timing at the gNB and UE can be aligned. These examples show additional details of the signaling and procedures. Figure 6 and Figure 7 The examples in the above example can be applied to Figure 5B Variant V1 described. But it may also be applicable to other variants. A single RTT response message directed to a specific gNB(i) includes in its payload (timestamp(s) (Δt(i)+TA), where Δt(i) represents the arrival time of the RTT measurement signal received from gNB(i) and TA represents the uplink timing adjustment parameter of the UE. A common RTT response message includes in its payload a set of timestamps (Δt(i)+TA) corresponding to the RTT measurement signals from all measured gNBs. These timestamps (Δt(i)+TA) may be organized in other ways known to a person skilled in the art.

[0104] The network may allocate low reuse resources to the UE to transmit the RTT response message(s). In any case, each gNB(i) that receives the RTT response message records 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 according to an aspect of the present disclosure is illustrated. Figure 6 As shown in FIG. 1 , in a (low duty cycle) downlink-centric / downlink-only subframe 602, the serving gNB 622 sends a control signal to the UE 102 during the first two symbol periods of the downlink subframe 602 (e.g., on a physical downlink control channel (PDCCH)), thereby indicating to the UE 102 that one or more gNBs ( Figure 6 In the example, the serving gNB 622, gNB 624 and gNB 626) will transmit a downlink RTT measurement (RTTM) signal.

[0106] During downlink subframes 606 and 608, gNB 624 and gNB 626 transmit downlink RTT measurement signals in a time division multiplexed (TDM) or frequency division multiplexed (FDM) manner (as illustrated by the horizontal subdivision of the individual symbols of downlink subframes 606 and 608) at designated (designated by the network (e.g., location server 170 or serving gNB 622)) symbols of downlink subframes 606 and 608. Although not illustrated, serving gNB 622 may also transmit downlink RTT measurement signals (also referred to as RTT measurement signals) during downlink subframe 602. The downlink RTT measurement signals transmitted by gNBs 622-626 may be wideband signals to enable UE 102 to make precise timing measurements. No other gNB in ​​the vicinity may transmit other signals within or around the symbols associated with these downlink RTT measurement signals (thereby 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 on the PDCCH from serving gNB 622. That is, UE 102 sets the start time of its PDCCH subframe to the time at which it receives the downlink signal from serving gNB 622.

[0108] UE 102 is instructed to report, during a subsequent uplink subframe, its RTT measurements (i.e., arrival time measurements Δt(i)) made during uplink subframe 612 of RTT measurement signals transmitted by gNBs 622-626 on the physical uplink shared channel (PUSCH). This uplink RTT report (also called an RTT response) from UE 102 may include the arrival time Δt(i) of each measured downlink RTT measurement signal (wherein the RTT report is a “common” report) and the UE 102’s own uplink timing adjustment (TA) provided by the serving gNB 622. Like the downlink RTT measurement signals transmitted by gNBs 622-626, the uplink RTT reports transmitted by UE 102 should be wideband signals to enable each gNB to make precise timing measurements of their arrival. Each gNB in ​​the neighborhood of UE 102 (i.e., each gNB within the communication range of UE 102; in the case of a gNB in ​​the neighborhood of UE 102) shall report the arrival time Δt(i) of each measured downlink RTT measurement signal. Figure 6 In the example of gNB 622-626, uplink RTT report is received from UE 102. Figure 6 In the example of FIG. 6 , gNB 624 receives an 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. Each gNB(i) may then calculate the RTT between the gNB(i) and UE 102 based on the arrival time of the uplink RTT report from UE 102, combined 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 accounts for the distance of UE 102 from the serving gNB 622. More specifically, the timing adjustment is the time starting from the time slot (e.g., OFDM symbol 211) in which UE 102 is permitted to transmit a traffic burst to prevent collisions with neighboring UEs. The timing adjustment enables all uplink signals from UE 102 to arrive at the serving gNB 622 at the same time. The uplink timing adjustment enables the uplink RTT report to arrive at the end of the gap following the PDCCH with the required accuracy.

[0110] UE-centric RTT estimation is similar to the network-based approach described above, except that a UE (e.g., UE 102) transmits uplink RTT measurement signal(s) (when instructed) 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 at the gNB(i) in the message payload. The UE determines the arrival time ΔT(i) of the downlink RTT response message from each gNB(i), decodes the RTT response message and 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-centric RTT estimation technique according to an aspect of the present disclosure is illustrated. On a (low duty cycle) uplink centric subframe 702, the serving gNB 622 sends a control signal to the UE 102 (e.g., on the PDCCH), thereby instructing the UE 102 (and potentially any number of other UEs) to transmit one or more uplink RTT measurement signals (UL-RTTM).

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

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

[0114] UE 102 and possibly each UE in the neighborhood (e.g., some or all UEs within 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 responses from the corresponding gNB(i) in gNBs 622-626 relative to its own (downlink) system time.

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

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

[0117] Transmit "beamforming" is a technique for focusing an RF signal in a particular direction. Traditionally, when a base station broadcasts an RF signal, it broadcasts the signal in all directions (omnidirectionally) or over a wide range of angles (e.g., over a cell sector). With 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 particular direction, thereby providing a faster (in terms of data rate) and stronger RF signal to the receiving device(s). In order to change the directionality of the RF signal while transmitting, the base station can control the phase and relative amplitude of the RF signal at each transmitter. For example, a base station can use an antenna array (referred to as a "phased array" or "antenna array") that produces a beam of RF waves that can be "steered" to point in different directions without actually moving the antennas. Specifically, RF currents from the transmitter are fed to the individual antennas in the correct phase relationship so that the radio waves from the separate antennas add together in desired directions to increase radiation, while canceling in undesired directions to suppress radiation.

[0118] In receive beamforming, a receiver uses a receive beam to amplify an RF signal detected on a given channel. For example, the receiver may increase a gain setting and / or adjust a phase setting of an array of antennas in a particular direction to amplify RF signals received from that direction (e.g., to increase their gain level). Thus, when a receiver is said to be beamforming in a certain direction, it means that the beam gain in that direction is high relative to the beam gain in other directions, or the beam gain in that direction is the highest compared to the beam gain 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 for communicating with a base station (e.g., on a carrier), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) for distinguishing adjacent cells operating via the same or different carriers. In some examples, a carrier may support multiple cells, and different cells may 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 may provide access to different types of devices. In some cases, the term "cell" may refer to a portion of a geographic coverage area (e.g., a sector) on which the logical entity operates.

[0120] Figure 8An exemplary system according to an aspect of the present disclosure is illustrated in which the RTT estimation procedures disclosed herein are extended to massive MIMO and mmW systems. Figure 8 In 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" to transmit 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 carry (implicitly or explicitly) 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 timestamp (e.g., arrival time) described earlier, the UE also records or reports the beam index (or multiple beam indices) or other beam identity (or multiple other beam identities) of the received RTT signal. The recorded beam index (or multiple beam indices) can be used to identify the downlink (DL) beam measured by UE 102 and determine the associated angle of departure (AOD) of each identified DL beam from the transmitting gNB towards UE 102. The AOD can be used to determine the estimated direction from the gNB to UE 102.

[0121] During reception, the gNB 622-626 records / reports the receive beam index (or other receive beam identity) for which the RTT (measurement / response) signal is received from the UE 102, and (for UE-centric RTT estimation) includes this information in the RTT response payload along with the timestamp (e.g., arrival time) described earlier. Similar to the DL beams measured and identified by the UE 102, the receive beam index recorded (and reported) by the gNB 622-626 can be used to determine the associated angle of arrival (AOA) of each identified receive beam from the receiving gNB toward the UE 102. The AOA can be used to determine the estimated direction from the gNB to the UE 102.

[0122] As described above, when AOA and / or AOD are available to the UE, the position of the UE can be improved by using RTT, AOD and / or AOA to calculate the position of the UE. Figure 4 The described RTT based location determination of the UE (eg, making it more accurate).

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

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

[0125] When the signal is repeated with the same transmit beam, it is intended to support receive beam sweeping (plus coherent combining if desired) at the receiving endpoint (UE 102 or a gNB 622-626).

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

[0127] Fig. 9 An exemplary method 900 for calculating the RTT of a UE (e.g., UE 102) performed by a master node (e.g., a serving base station or a non-serving base station (e.g., any of gNB 502, 622-626)) is illustrated. The method 900 may be performed by, for example, Figure 3The communication device 314 and / or the processing system 334 of the apparatus 304 in the embodiment of the present invention are executed based on the execution of the RTT measurement component 354. At 902, a master node (e.g., the communication device 314) sends a plurality of downlink RTT measurement signals to a 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., processing system 334) calculates the RTT between the UE and the master node based on a combination of the arrival times of the multiple 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] Fig.10 An exemplary method 1000 for calculating RTT at a UE (e.g., UE 102) is illustrated. The method 1000 may be performed by, for example, Figure 3 The communication device 308 and / or the processing system 334 in the embodiment is executed based on the execution of the RTT measurement component 352.

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

[0130] At 1004, UE 102 (e.g., communication device 308 or processing system 332 of communication device 308) transmits an uplink RTT measurement signal to one or more base stations (e.g., any of gNB 502, 622-626) during a predefined resource block of a subframe, wherein at least one of the one or more base stations measures an arrival time of the uplink RTT measurement signal relative to a 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 a 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 an 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, UE 102 (e.g., communication device 308) calculates the RTT between UE 102 and the at least one base station based on the arrival time of the downlink RTT response to UE 102, the timing adjustment parameter of UE 102, and the arrival time of the uplink RTT measurement signal relative to the downlink system time of UE 102. UE 102 receives the 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 UE 102.

[0133] Fig.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 gNB 502, 622-626), according to various 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 the embodiment executes based on the execution of the RTT measurement component 354.

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

[0135] At 1104, a master node (e.g., a communication device 314) receives information from a UE indicating an arrival time of each of a plurality of RTT measurement signals at the UE, wherein the plurality of RTT measurement signals include 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 a 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 RTT measurement signal of the plurality of RTT measurement signals on one or more transmit beams, wherein the UE reports an identity of at least one transmit beam of the one or more transmit beams, wherein the identity of the at least one transmit beam enables determination of an 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 a low reuse resource. In one aspect, the master node and at least one of the multiple other nodes receive the RTT response on one or more receive beams, wherein 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 multiple other nodes utilize multiple receive beams, wherein, based on the master node and the at least one of the multiple other nodes having a hardware receiver chain less than the number of the multiple receive beams, the UE transmits the RTT response multiple times to permit the master node and the at least one of the multiple other nodes to sequentially cycle through all receive beams in the multiple 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 (eg, processing system 334) obtains the arrival time of the RTT response signal arriving at the master node.

[0138] At 1110, the master node (e.g., processing system 334) obtains a 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: (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) determining the transmission time of the RTT response signal by the master node and sending 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., the communication device 314) receives information indicating the RTT between the UE and each of the multiple other nodes from the multiple other nodes. In one aspect, the information indicating the RTT between the UE and each of the multiple other nodes may include information indicating a transmission time of each RTT measurement signal transmitted by the multiple other nodes and information indicating an arrival time of the RTT response signal arriving at each of the multiple other nodes.

[0140] At 1114, the master node (e.g., the communication device 314 or the processing system 334) determines 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 the following: the transmission time of the downlink RTT measurement signal at the master node, information indicating the arrival time of each of the multiple 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 multiple other nodes, and a 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 the location server at least one of: a transmission time of the downlink 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.

[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 multiple other nodes will transmit the multiple RTT measurement signals during multiple predefined code elements of the 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 of each RTT measurement signal in the multiple RTT measurement signals to the UE. The UE may include information indicating the arrival time of each RTT measurement signal in the multiple RTT measurement signals to the UE in the payload of the RTT response signal. In this case, the reception at 1104 may include: decoding the payload of the RTT response signal. Each of the multiple other nodes may calculate the corresponding RTT between the UE and each of the nodes based on: (1) the transmission time of a downlink RTT measurement signal among the multiple other RTT measurement signals transmitted by each of the nodes at the each of the nodes, (2) information indicating the arrival time of each of the multiple RTT measurement signals at the UE included in the payload of the RTT response signal, (3) the arrival time of the RTT response signal at each of the nodes, and (4) the transmission time of the RTT response signal, wherein each of the nodes determines the transmission time of the RTT response signal and the information indicating the arrival time of each of the multiple RTT measurement signals at the UE included in the payload of the RTT response signal by demodulating and decoding the RTT response signal, wherein the information indicating the RTT between the UE and each of the nodes received by the master node from each of the nodes includes the calculated corresponding RTT.

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

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

[0145] At 1202, a UE (e.g., communication device 308) transmits an RTT measurement signal to a plurality of base stations (e.g., any of gNBs 502, 622-626), wherein each 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. In one aspect, the plurality of base stations may be neighboring base stations within a communication range of the UE. In one aspect, the UE may transmit the RTT measurement signal on a PUSCH. In one aspect, the RTT measurement signal may be a broadband signal.

[0146] In one aspect, 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. In one aspect, the at least one base station may utilize a plurality of receive beams, and wherein, based on the at least one base station having fewer hardware receiver chains than the plurality of receive beams, the UE receives a command to transmit the RTT measurement signal multiple times to permit the at least one base station to sequentially cycle through all of the plurality of receive beams that may 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 from the UE. In one aspect, at least one of the multiple base stations may transmit the RTT response signal on each of the one or more transmit beams of the at least one base station. In one aspect, the RTT measurement signal and the RTT response signal may be transmitted on low reuse resources.

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

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

[0150] At 1208, the UE calculates 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 of the RTT response signal received from each of the multiple base stations at the UE, information about each of the multiple 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. The UE may receive the timing adjustment parameter from the UE's serving base station.

[0151] On the one hand, although Fig.12 Not illustrated in, but method 1200 may further include: receiving 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. In one aspect, the UE may receive the control signal on a PDCCH.

[0152] On the one hand, although Fig.12 Not illustrated, but method 1200 may further include: receiving an instruction from a serving base station of the UE to scan for RTT response signals received from each of the multiple base stations.

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

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

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

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

[0157] Figure 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 boxes can be implemented as a processing system including one or more processor components. In some designs, the functionality of these modules can be implemented using, for example, at least a portion of one or more integrated circuits (e.g., AISCs). As discussed herein, an integrated circuit may include a processor, software, other related components, or some combination thereof. Therefore, the functionality of different modules can be implemented, for example, as different subsets of integrated circuits, different subsets of software module sets, or a combination thereof. Similarly, it will be appreciated that a given subset (e.g., of an integrated circuit and / or software module set) can provide at least a portion of the functionality of more than one module.

[0158] in addition, Figure 13-16 The components and functions represented and other components and functions described herein may be implemented using any suitable means. Such means may also be implemented at least in part using corresponding structures taught herein. For example, the above combined Figure 13-16 Components described by “means for…” components may also correspond to similarly named “means for…” functionality. Thus, in some aspects, one or more of such means may 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 may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0160] In addition, those skilled in the art will appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the aspects disclosed herein can be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician can implement the described functionality in different ways for each specific 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 conjunction with the various aspects disclosed herein may be implemented or executed 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 an 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, for example, 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 conjunction with the various 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 module may reside in a random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read / write information from / to the storage medium. Alternatively, a storage medium may be integrated into a processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). In an alternative, the processor and storage medium may reside in a user terminal as discrete components.

[0163] In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any media that facilitates the transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a computer. As an example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces 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 present invention as defined by the appended claims. The functions, steps, and / or actions in the method claims according to the various aspects of the present disclosure described herein do not have to be performed in any particular order. In addition, although the elements of the present disclosure may be described or claimed in the singular, the plural is also contemplated unless limitation to the singular is explicitly stated.

Claims

1. A wireless positioning method performed by a user equipment (UE), comprising: receiving a plurality of first round trip time (RTT) signals from a plurality of base stations; transmitting a second RTT signal to the plurality of base stations, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; as well as transmitting a plurality of first time difference measurements corresponding to the plurality of base stations to a network entity, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of one of the plurality of first RTT signals at the UE and a transmission time of the second RTT signal leaving the UE, wherein the plurality of first time difference measurements enable the network entity to calculate a plurality of RTTs between the UE and the plurality of base stations based on the plurality of first time difference measurements, a timing adjustment parameter of the UE, and a plurality of second time difference measurements, each second time difference measurement in the plurality of second time difference measurements representing a difference between an arrival time of the second RTT signal at one of the plurality of base stations and a transmission time of one of the plurality of first RTT signals leaving the base station, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

2. The method of claim 1, wherein: The plurality of first RTT signals are a plurality of RTT measurement signals, and The first RTT signal is an RTT response signal.

3. The method of claim 1, further comprising: The timing adjustment parameter is received from a serving base station of the UE.

4. The method of claim 1, wherein the plurality of base stations include neighboring base stations within a communication range of the UE. The method of claim 1 , wherein the network entity is a serving base station. The method of claim 1 , wherein the network entity is a location server.

7. A wireless positioning method performed by a first base station, comprising: transmitting a first round trip time (RTT) signal to a user equipment (UE); receiving a second RTT signal from the UE, wherein the second RTT signal is received after transmitting the first RTT signal; as well as transmitting a first time difference measurement to a network entity, the first time difference measurement representing a difference between a transmission time of the first RTT signal leaving the first base station and an arrival time of the second RTT signal at the first base station, wherein the time difference measurement enables the network entity to calculate a plurality of RTTs between the UE and a plurality of base stations including the first base station based on a plurality of first time difference measurements including the first time difference measurement, a plurality of second time difference measurements, and a timing adjustment parameter of the UE, the plurality of first time difference measurements representing differences between arrival times of the second RTT signals at the plurality of base stations and transmission times of a plurality of first RTT signals including the first RTT signal leaving the plurality of base stations, the plurality of second time difference measurements representing differences between arrival times of the plurality of first RTT signals at the UE and transmission times of the second RTT signals leaving the UE, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

8. The method of claim 7, wherein: The first RTT signal is an RTT measurement signal, and The second RTT signal is an RTT response signal.

9. The method of claim 7, further comprising: The timing adjustment parameter is transmitted to the network entity, wherein the first base station is a serving base station of the UE.

10. The method of claim 7, wherein the first base station is a serving base station of the UE.

11. The method of claim 7, wherein the first base station is a neighboring base station within a communication range of the UE.

12. The method of claim 7, wherein the network entity is a location server.

13. A wireless positioning method performed by a network entity, comprising: receiving, from a user equipment (UE), a plurality of first time difference measurements corresponding to a plurality of base stations, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of a first RTT signal of a plurality of first RTT signals at the UE and a transmission time of a second RTT signal leaving the UE, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; receiving a plurality of second time difference measurements from the plurality of base stations, each second time difference measurement in the plurality of second time difference measurements representing a difference between a transmission time of one of the plurality of first RTT signals from one of the plurality of base stations and an arrival time of the second RTT signal at the base station; as well as The position of the UE is estimated based at least on the plurality of first time difference measurements, the plurality of second time difference measurements, and a timing adjustment parameter of the UE, wherein the timing adjustment parameter indicates an amount of time that a UE transmission timing leads a base station reception timing.

14. The method of claim 13, wherein estimating the location of the UE comprises: A plurality of RTTs between the UE and the plurality of base stations are calculated based on the plurality of first time difference measurements and the plurality of second time difference measurements.

15. The method of claim 14, wherein the location of the UE is further estimated based on known locations of the plurality of base stations.

16. The method of claim 13, further comprising: The timing adjustment parameter is received from a serving base station of the UE.

17. The method of claim 13, wherein: The plurality of first RTT signals are a plurality of RTT measurement signals, and The second RTT signal is an RTT response signal.

18. The method of claim 13, wherein the plurality of base stations include neighboring base stations within a communication range of the UE.

19. The method of claim 13, wherein the network entity is a location server.

20. A user equipment (UE), comprising: Memory; at least one transceiver; as well as at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receiving, via the at least one transceiver, a plurality of first round trip time (RTT) signals from a plurality of base stations; transmitting, via the at least one transceiver, a second RTT signal to the plurality of base stations, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; as well as transmitting, via the at least one transceiver, to a network entity a plurality of first time difference measurements corresponding to the plurality of base stations, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of one of the plurality of first RTT signals at the UE and a transmission time of the second RTT signal leaving the UE, wherein the plurality of first time difference measurements enable the network entity to calculate a plurality of RTTs between the UE and the plurality of base stations based on the plurality of first time difference measurements, a timing adjustment parameter of the UE, and a plurality of second time difference measurements, each second time difference measurement in the plurality of second time difference measurements representing a difference between an arrival time of the second RTT signal at one of the plurality of base stations and a transmission time of one of the plurality of first RTT signals leaving the base station, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

21. The UE of claim 20, wherein: The plurality of first RTT signals are a plurality of RTT measurement signals, and The first RTT signal is an RTT response signal.

22. The UE of claim 20, wherein the at least one processor is further configured to: The timing adjustment parameter is received from a serving base station of the UE via the at least one transceiver.

23. The UE of claim 20, wherein the plurality of base stations include neighboring base stations within a communication range of the UE.

24. The UE of claim 20, wherein the network entity is a serving base station.

25. The UE of claim 20, wherein the network entity is a location server.

26. A first base station, comprising: Memory; at least one transceiver; as well as at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: transmitting, via the at least one transceiver, a first round trip time (RTT) signal to a user equipment (UE); receiving, via the at least one transceiver, a second RTT signal from the UE, wherein the second RTT signal is received after transmitting the first RTT signal; as well as transmitting, via the at least one transceiver, to a network entity a first time difference measurement representing a difference between a transmission time of the first RTT signal leaving the first base station and an arrival time of the second RTT signal at the first base station, wherein the time difference measurement enables the network entity to calculate a plurality of RTTs between the UE and a plurality of base stations including the first base station based on a plurality of first time difference measurements including the first time difference measurement, a plurality of second time difference measurements, and a timing adjustment parameter of the UE, the plurality of first time difference measurements representing differences between arrival times of the second RTT signals at the plurality of base stations and transmission times of a plurality of first RTT signals including the first RTT signal leaving the plurality of base stations, the plurality of second time difference measurements representing differences between arrival times of the plurality of first RTT signals at the UE and transmission times of the second RTT signals leaving the UE, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

27. The first base station of claim 26, wherein: The first RTT signal is an RTT measurement signal, and The second RTT signal is an RTT response signal.

28. The first base station of claim 26, wherein the at least one processor is further configured to: The timing adjustment parameter is transmitted to the network entity via the at least one transceiver, wherein the first base station is a serving base station of the UE.

29. The first base station as claimed in claim 26, wherein the first base station is a serving base station of the UE.

30. The first base station of claim 26, wherein the first base station is a neighboring base station within a communication range of the UE.

31. The first base station of claim 26, wherein the network entity is a location server.

32. A network entity comprising: Memory; at least one transceiver; as well as at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receiving, via the at least one transceiver, from a user equipment (UE) a plurality of first time difference measurements corresponding to a plurality of base stations, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of a first RTT signal of a plurality of first RTT signals at the UE and a transmission time of a second RTT signal leaving the UE, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; receiving, via the at least one transceiver, a plurality of second time difference measurements from the plurality of base stations, each second time difference measurement in the plurality of second time difference measurements representing a difference between a transmission time of one of the plurality of first RTT signals from one of the plurality of base stations and an arrival time of the second RTT signal at the base station; as well as The position of the UE is estimated based at least on the plurality of first time difference measurements, the plurality of second time difference measurements, and a timing adjustment parameter of the UE, wherein the timing adjustment parameter indicates an amount of time that a UE transmission timing leads a base station reception timing.

33. The network entity of claim 32, wherein the at least one processor being configured to estimate the location of the UE comprises the at least one processor being configured to: A plurality of RTTs between the UE and the plurality of base stations are calculated based on the plurality of first time difference measurements and the plurality of second time difference measurements.

34. The network entity of claim 33, wherein the location of the UE is further estimated based on known locations of the plurality of base stations.

35. The network entity of claim 32, wherein the at least one processor is further configured to: The timing adjustment parameter is received from a serving base station of the UE via the at least one transceiver.

36. The network entity of claim 32, wherein: The plurality of first RTT signals are a plurality of RTT measurement signals, and The second RTT signal is an RTT response signal.

37. The network entity of claim 32, wherein the plurality of base stations include neighboring base stations within a communication range of the UE.

38. The network entity of claim 32, wherein the network entity is a location server.

39. A user equipment (UE), comprising: means for receiving a plurality of first round trip time (RTT) signals from a plurality of base stations; means for transmitting a second RTT signal to the plurality of base stations, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; as well as means for transmitting to a network entity a plurality of first time difference measurements corresponding to the plurality of base stations, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of one of the plurality of first RTT signals at the UE and a transmission time of the second RTT signal leaving the UE, wherein the plurality of first time difference measurements enable the network entity to calculate a plurality of RTTs between the UE and the plurality of base stations based on the plurality of first time difference measurements, a timing adjustment parameter of the UE, and a plurality of second time difference measurements, each second time difference measurement in the plurality of second time difference measurements representing a difference between an arrival time of the second RTT signal at one of the plurality of base stations and a transmission time of one of the plurality of first RTT signals leaving the base station, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

40. A first base station, comprising: means for transmitting a first round trip time (RTT) signal to a user equipment (UE); means for receiving a second RTT signal from the UE, wherein the second RTT signal is received after transmitting the first RTT signal; as well as means for transmitting a first time difference measurement to a network entity, the first time difference measurement representing a difference between a transmission time of the first RTT signal leaving the first base station and an arrival time of the second RTT signal at the first base station, wherein the time difference measurement enables the network entity to calculate a plurality of RTTs between the UE and a plurality of base stations including the first base station based on a plurality of first time difference measurements including the first time difference measurement, a plurality of second time difference measurements, and a timing adjustment parameter of the UE, the plurality of first time difference measurements representing differences between arrival times of the second RTT signals at the plurality of base stations and transmission times of a plurality of first RTT signals including the first RTT signal leaving the plurality of base stations, the plurality of second time difference measurements representing differences between arrival times of the plurality of first RTT signals at the UE and transmission times of the second RTT signals leaving the UE, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

41. A network entity comprising: means for receiving, from a user equipment (UE), a plurality of first time difference measurements corresponding to a plurality of base stations, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of a first RTT signal of a plurality of first RTT signals at the UE and a transmission time of a second RTT signal leaving the UE, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; means for receiving a plurality of second time difference measurements from the plurality of base stations, each second time difference measurement of the plurality of second time difference measurements representing a difference between a transmission time of one of the plurality of first RTT signals from one of the plurality of base stations and an arrival time of the second RTT signal at the base station; as well as means for estimating a position of the UE based at least on the plurality of first time difference measurements, the plurality of second time difference measurements, and a timing adjustment parameter of the UE, wherein the timing adjustment parameter indicates an amount of time that a UE transmission timing leads a base station reception timing.

42. A non-transitory computer-readable medium storing computer-executable instructions which, when executed by a user equipment (UE), cause the UE to: receiving a plurality of first round trip time (RTT) signals from a plurality of base stations; transmitting a second RTT signal to the plurality of base stations, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; as well as transmitting a plurality of first time difference measurements corresponding to the plurality of base stations to a network entity, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of one of the plurality of first RTT signals at the UE and a transmission time of the second RTT signal leaving the UE, wherein the plurality of first time difference measurements enable the network entity to calculate a plurality of RTTs between the UE and the plurality of base stations based on the plurality of first time difference measurements, a timing adjustment parameter of the UE, and a plurality of second time difference measurements, each second time difference measurement in the plurality of second time difference measurements representing a difference between an arrival time of the second RTT signal at one of the plurality of base stations and a transmission time of one of the plurality of first RTT signals leaving the base station, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

43. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a first base station, cause the first base station to: transmitting a first round trip time (RTT) signal to a user equipment (UE); receiving a second RTT signal from the UE, wherein the second RTT signal is received after transmitting the first RTT signal; and transmitting a first time difference measurement to a network entity, the first time difference measurement representing a difference between a transmission time of the first RTT signal leaving the first base station and an arrival time of the second RTT signal at the first base station, wherein the time difference measurement enables the network entity to calculate a plurality of RTTs between the UE and a plurality of base stations including the first base station based on a plurality of first time difference measurements including the first time difference measurement, a plurality of second time difference measurements, and a timing adjustment parameter of the UE, the plurality of first time difference measurements representing differences between arrival times of the second RTT signals at the plurality of base stations and transmission times of a plurality of first RTT signals including the first RTT signal leaving the plurality of base stations, the plurality of second time difference measurements representing differences between arrival times of the plurality of first RTT signals at the UE and transmission times of the second RTT signals leaving the UE, and The timing adjustment parameter indicates the amount of time that the UE transmission timing leads the base station reception timing.

44. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a network entity, cause the network entity to: receiving, from a user equipment (UE), a plurality of first time difference measurements corresponding to a plurality of base stations, each first time difference measurement of the plurality of first time difference measurements representing a difference between an arrival time of a first RTT signal of a plurality of first RTT signals at the UE and a transmission time of a second RTT signal leaving the UE, wherein the second RTT signal is transmitted after receiving the plurality of first RTT signals; receiving a plurality of second time difference measurements from the plurality of base stations, each second time difference measurement indicative of a difference between a transmission time of one of the plurality of first RTT signals from one of the plurality of base stations and an arrival time of the second RTT signal at the base station; and The position of the UE is estimated based at least on the plurality of first time difference measurements, the plurality of second time difference measurements, and a timing adjustment parameter of the UE, wherein the timing adjustment parameter indicates an amount of time that a UE transmission timing leads a base station reception timing.

Images