Sounding reference signal (SRS) transmission for positioning on flexible symbol

Abstract

To provide a method of transmitting Sounding Reference Signal (SRS) for positioning utilized on flexible symbols, a mobile device, and a non-transitory computer readable medium.SOLUTION: In a wireless network, user equipment (UE) receives, from a serving base station, a message comprising an indication to transmit an SRS on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot, receives, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; and transmits the SRS on at least a portion of the subset based on receiving an indication, from the serving base station, that transmitting the SRS on Flexible symbols is allowable.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of wireless communications, and more particularly to determining the location or position of mobile electronic devices in wireless communications networks. [Background technology]

[0002] Determining the location of a mobile electronic device (herein referred to as user equipment (UE)) in a wireless network uses wireless radio frequency (RF) signaling between the UE and the network's terrestrial transceiver. In a fifth-generation new wireless (5G NR, also referred to herein simply as "NR") wireless network defined by the 3rd Generation Partnership Project (3GPP®), positioning techniques can include downlink (DL)-only positioning methods, uplink (UL)-only positioning methods, and DL+UL positioning methods. For the UL-only and DL+UL positioning methods, the UL signal (the signal sent from the UE to the terrestrial transceiver (base station)) can comprise a sounding reference signal (SRS), which can be communicated using symbols in orthogonal frequency division multiplexing (OFDM) slots designated for UL signaling. Summary of the Invention

[0003] An exemplary method for transmitting a reference signal for positioning in a user equipment (UE) according to the present disclosure comprises receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot. The method also comprises receiving, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible. The method also comprises transmitting the SRS for positioning on at least a portion of the subset.

[0004] An exemplary mobile device according to the present disclosure comprises a wireless transceiver, a memory, and one or more processing units communicatively coupled to the wireless transceiver and the memory. The one or more processing units are configured to receive, from a serving base station, via the wireless transceiver, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot. The one or more processing units are also configured to receive, from the serving base station, via the wireless transceiver, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible. The one or more processing units are also configured to transmit, via the wireless transceiver, the SRS for positioning on at least a portion of the subset.

[0005] An exemplary device according to the present disclosure comprises means for receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot. The device also comprises means for receiving, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible. The device also comprises means for transmitting an SRS for positioning on at least a portion of the subset.

[0006] An exemplary non-transitory computer-readable medium according to the present disclosure stores instructions comprising code for transmitting a reference signal for positioning. The instructions also comprise code for receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot. The instructions also comprise code for receiving, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible. The instructions also comprise code for transmitting the SRS for positioning on at least a portion of the subset. [Brief explanation of the drawings]

[0007] [Figure 1]

[0007] FIG. 1 is a diagram of a terrestrial positioning system, according to one embodiment. [Figure 2]

[0008] 2 illustrates an example of a frame structure that may be used in wireless communications in the positioning system of FIG. 1, according to one embodiment. [Figure 3]

[0009] 1 is a call flow diagram illustrating a method for sounding reference signal (SRS) transmission for positioning according to one embodiment. [Figure 4]

[0010] 4 is a flow diagram of a method for transmitting a reference signal for positioning, according to one embodiment. [Figure 5]

[0011] 1 is a block diagram of an embodiment of a user equipment (UE) that may be utilized as described herein. [Figure 6]

[0012] 1 is a block diagram of one embodiment of a base station that may be utilized as described herein. DETAILED DESCRIPTION OF THE INVENTION

[0008]

[0013] Like reference symbols in various drawings indicate like elements, according to some exemplary implementations. Furthermore, multiple instances of an element may be indicated by a first number for the element followed by a letter or a hyphen and a second number. For example, multiple instances of element 110 may be indicated as 110-1, 110-2, 110-3, etc., or as 110a, 110b, 110c, etc. When referring to such an element using only the first number, any instance of the element should be understood (e.g., element 110 in the previous example refers to elements 110-1, 110-2, and 110-3, or to elements 110a, 110b, and 110c).

[0009]

[0014] Several exemplary embodiments are now described with reference to the accompanying drawings, which form a part of this application. Although specific embodiments in which one or more aspects of the present disclosure may be implemented are described below, other embodiments may be used and various changes may be made without departing from the scope of the present disclosure.

[0010]

[0015] As used herein, an "RF signal" or "wireless signal" comprises electromagnetic waves that transport information through space between a transmitter or transmitting device and a receiver or receiving device. As used herein, a transmitter may transmit one or more RF / wireless signals to a receiver. As described in further detail herein, an RF / wireless signal may comprise an uplink (UL) signal and / or a downlink (DL) signal, which may reflect the type of device transmitting the signal and / or the receiving device receiving the signal. For each RF / wireless signal transmitted by a transmitter, a receiver may receive multiple corresponding wireless / RF signals due to the propagation characteristics of the RF signal through a multipath channel. The same transmitted RF signal on different paths between the transmitter and receiver may be referred to as a "multipath" RF signal.

[0011]

[0016] 1 is a diagram of a terrestrial positioning system 100, according to one embodiment, wherein the terrestrial positioning system comprises a portion of a wireless data communications network (e.g., a mobile broadband network) having multiple transceivers known as base stations 110-1, 110-2, and 110-3 (collectively and collectively referred to herein as base stations 110) that are used to determine a location (e.g., in geographic coordinates) of a UE 120. The base stations 110 and / or the UE 120 may both be communicatively coupled to a location server 130 via a wide area network (WAN) 140. As described in further detail below, the location of the UE 120 may be determined based on wireless signals communicated between the UE 120 and the various base stations 110.

[0012]

[0017] It should be noted that FIG. 1 provides a generalized illustration of various components, any or all of which may be utilized as appropriate, and that each of which may be duplicated or omitted as needed. In particular, while one UE 120 is shown, it will be understood that many UEs (e.g., hundreds, thousands, millions, etc.) may utilize the terrestrial positioning system 100. Similarly, the terrestrial positioning system 100 may include more or fewer base stations 110, location servers 130, and / or other components. The illustrated communication links communicatively connecting the various components in the terrestrial positioning system 100 include data and signaling connections, which may include additional (intermediate) components, direct or indirect physical (wired) and / or wireless connections, and / or additional networks. Furthermore, components may be rearranged, combined, separated, substituted, and / or omitted depending on the desired functionality. Moreover, in a given scenario, the UE 120 may communicate with more or fewer base stations 110, which may still be used to determine the location of the UE 120. Generally, the more base stations 110 with which the UE 120 can exchange wireless signals 150 (involved in a DL-only positioning method, a UL-only positioning method, and / or a DL+UL positioning method), the more accurate the positioning of the UE 120 will be.

[0013]

[0018] As used herein, UE 120 may be an electronic device and may also be referred to as a device, a mobile device, a wireless device, a mobile terminal, a terminal, a wireless terminal, a mobile station (MS), a Secure User Plane Location (SUPL)-Enabled Terminal (SET), or by some other name. Additionally, UE 120 may correspond to a cell phone, a smartphone, a laptop, a tablet, a personal digital assistant (PDA), a tracking device, a wearable device, an Internet of Things (IoT) device, or some other portable or movable device. In some cases, UE 120 may be part of some other entity, such as a chipset supporting a modem embedded in some larger mobile entity, such as a vehicle, a drone, a package, a transport, a robotic device, etc. As mentioned, UE 120 can support wireless communications under the 5G NR standard. That said, the UE 120 may support wireless communications using one or more additional radio access technologies (RATs), such as Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), Long Term Evolution (LTE), High Rate Packet Data (HRPD), IEEE 802.11 Wi-Fi, Bluetooth (BT), Worldwide Interoperability for Microwave Access (WiMAX), etc. The UE 120 may also support wireless communications using a wireless local area network (WLAN), which may connect to other networks (e.g., the Internet) using, for example, a digital subscriber line (DSL) or packet cable. Additionally, while the embodiments provided herein are directed to SRS transmission by the UE 120 under 5G NR, alternative embodiments may extend to other forms of wireless communications.

[0014]

[0019] UE 120 may comprise a single entity or may comprise multiple entities, such as in a personal area network where a user may employ audio, video, and / or data I / O devices and / or body sensors and a separate wireline or wireless modem. An estimate of the location of UE 120 may be referred to as a location, location estimate, location fix, fix, position, position estimate, or position fix, and may be geodetic and thus provide location coordinates (e.g., latitude and longitude) of UE 120 that may or may not include an altitude component (e.g., height above sea level, height or depth above ground, floor level or basement level). Alternatively, the location of UE 120 may be expressed as a civic location (e.g., as a postal address or as a designation of some point or small area in a building, such as a particular room or floor). The location of UE 120 may also be expressed as an area or volume (defined either geodesically or in urban form) within which UE 120 is expected to be located with some probability or confidence level (e.g., 67%, 95%, etc.). The location of UE 120 may also be a relative location comprising distance and direction or relative X, Y (and, optionally, Z) coordinates defined relative to some origin at a known location, which may be defined, for example, geodetically, with respect to a city, or by reference to a point, area, or volume shown on a map, floor plan, or building plan. In the description contained herein, use of the term location may comprise any of these variations unless otherwise specified. When calculating the location of a UE, it is common to determine the values ​​of the local X, Y, and possibly Z coordinates and then, if necessary, convert the local coordinates to absolute coordinates (e.g., for latitude, longitude, and altitude above or below mean sea level).

[0015]

[0020] Depending on the desired functionality, WAN 140 may comprise any of a variety of wireless and / or wireline communication networks. WAN 140 may comprise, for example, any combination of public and / or private networks, local and / or wide area networks, etc. Additionally, WAN 140 may utilize one or more wired and / or wireless communication technologies (such as one or more of the wireless communication technologies described above). In some embodiments, WAN 140 may comprise, for example, a cellular or other mobile network, a WLAN, a wireless wide area network (WWAN), and / or the Internet.

[0016]

[0021] The base station 110 may comprise a node of (or otherwise communicatively coupled to) the WAN 140 that may enable the UE 120 to wirelessly communicate with other devices linked to the WAN 140. The location of the UE 120 may be further determined using wireless signals 150 (as described in more detail below) and the known location of the base station 110. It may further be noted that the techniques are not necessarily limited to fixed base stations (i.e., base stations having fixed locations), but may also include mobile base stations. In a 5G NR network (e.g., when the WAN 140 comprises a wireless data network supporting 5G NR communications), each base station 110 may comprise a transmit receiving point (TRP), such as an NR Node B (gNB) and / or an antenna of a gNB. Additionally or alternatively, the base station 110 may comprise a Node B, an evolved Node B (eNode B or eNB), a base transceiver station (BTS), a radio base station (RBS), or a next generation eNB (ng-eNB). Thus, by accessing the WAN 140, the UE 120 can send and receive information about network-connected devices, such as the location server 130.

[0017]

[0022] Solid arrows between components indicate communication links. Also as shown, the UE 120 may access the WAN 140 through the first base station 110-1 (via wireless signals 150 between the UE 120 and the first base station 110-1). Thus, the first base station 110-1 serves as a serving base station for the UE 120. As one skilled in the art will appreciate, other base stations 110 may be serving base stations for the UE 120 depending on factors such as the location of the UE 120. In the example shown in FIG. 1 , when the first base station 110-1 serves as a serving base station, the other base stations 110-2 and 110-3 with which the UE 120 can exchange wireless signals 150 may serve as neighboring base stations 110-2 and 110-3, which may provide additional throughput and bandwidth to the UE 120 and / or provide the positioning functionality described herein.

[0018]

[0023] Location server 130 may comprise a server and / or other computing device configured to determine an estimated location of UE 120 and / or provide data (e.g., “assistance data”) to UE 120 to facilitate location determination. According to some embodiments, location server 130 may comprise a SUPL Location Platform (SLP) that may support a Secure User Plane Location (SUPL) user plane (UP) location solution defined by the Open Mobile Alliance (OMA) and may support location services for UE 120 based on subscription information for UE 120 stored in location server 130. Location server 130 may also comprise an Enhanced Serving Mobile Location Center (E-SMLC) that supports the location of UE 120 using a control plane (CP) location solution for LTE radio access by UE 120. Location server 130 may further comprise a Location Management Function (LMF) that supports the location of UE 120 using a control plane (CP) location solution for 5G NR radio access by UE 120. In a CP location solution, signaling for controlling and managing the location of UE 120 may be exchanged between elements of WAN 140 and with UE 120 using existing network interfaces and protocols, and as signaling from the perspective of WAN 140. In a UP location solution, signaling for controlling and managing the location of UE 120 may be exchanged between location server 130 and UE 120 as data from the perspective of WAN 140 (e.g., data transported using Internet Protocol (IP) and / or Transmission Control Protocol (TCP)).

[0019]

[0024] Additionally, it may be noted that in some embodiments of the terrestrial positioning system 100, the location server 130 may be executed by and / or incorporated into the UE 120 itself. That is, in the embodiments described herein, the functionality of the location server 130 may be performed by the UE 120. In such cases, communication between the UE and the location server may therefore occur between hardware and / or software components of the UE 120. Similarly, the functionality of the location server 130 described herein may be performed by a base station 110 or other device communicatively coupled to the terrestrial positioning system 100.

[0020]

[0025] FIG. 2 illustrates an example of a frame structure for NR and related terminology that can serve as a basis for physical layer communications between UE 120 and a base station 110, such as serving base station 210-1. The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each 1 ms long, indexed from 0 to 9. Each subframe may include a variable number of slots depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods within each slot may be assigned an index. A minislot may have a subslot structure (e.g., 2, 3, or 4 symbols). Also illustrated in FIG. 2 is a complete orthogonal frequency division multiplexing (OFDM) of a subframe, showing how the subframe may be divided into multiple resource blocks (RBs) across both time and frequency. A single RB may comprise a grid of resource elements (REs) spanning 14 symbols and 12 subcarriers.

[0021]

[0026] Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) or data transmission, and the link direction for each subframe may be dynamically switched. The link direction may be based on the slot format. Each slot may contain DL / UL data and DL / UL control information. In NR, a synchronization signal (SS) block is transmitted. The SS block includes a primary SS (PSS), a secondary SS (SSS), and a two-symbol physical broadcast channel (PBCH). The SS block may be transmitted at a fixed slot location, such as symbols 0 to 3, as shown in Figure 2. The PSS and SSS may be used by the UE for cell search and acquisition. The PSS may provide half-frame timing, and the SS may provide cyclic prefix (CP) length and frame timing. The PSS and SSS may provide cell identification information. The PBCH carries some basic system information, such as the downlink system bandwidth, timing information within the radio frame, SS burst set periodicity, and system frame number.

[0022]

[0027] As mentioned above, the terrestrial positioning system 100 can determine the location of the UE 120 using positioning techniques that can include a DL-only positioning method, a UL-only positioning method, or a DL+UL positioning method. For the UL-only and DL+UL positioning methods, the UL signal (the signal sent from the UE 120 to the base station 110) can comprise an SRS, which can be communicated using symbols in an OFDM slot designated for UL signaling. Positioning methods using the UL signal can include, for example, UL Time Difference of Arrival (UL-TDOA), UL Angle of Arrival (UL-AoA), and Round Trip Time (RTT) measurements from multiple base stations (known as multi-RTT), and can be based on the time difference, AoA, Reference Signal Received Power (RSRP), and / or other measurements of the SRS. In multi-RTT, for example, the distance between UE 120 and each base station 110 may be determined based at least in part on one or more SRS signals, and the location of UE 120 may be calculated as the location that satisfies the distance determination given the known locations of base stations 110. In UL-TDOA, the location of UE 120 may similarly be calculated based on the difference in time at which SRS signal(s) from UE 120 are received at different base stations 110 (e.g., by comparing signals received at different pairs of base stations and determining a common solution). In UL-AoA, each base station 110 may determine the angle at which SRS signal(s) from UE 120 are received, and multi-angulation may be used to determine a solution that satisfies the determined angle at each base station 110.

[0023]

[0028] The SRS transmitted by the UE 120 may comprise a frequency-domain reference signal sequence derived from a Zadoff-Chu sequence. While it may be used for other purposes, the SRS may be particularly useful for determining the location of the UE 120, as discussed above. Under 5G NR, the SRS may be sent periodically, semi-persistently, and / or aperiodically, depending on the desired functionality, and may be configured in any symbol of an NR OFDM slot. Moreover, multi-symbol SRS resources may be staggered in frequency. The serving base station 110-1 may provide the UE 120 with information regarding how and when to transmit the SRS, and the location server 130 may inform neighboring base stations 110-2 and 110-3 of these aspects of the SRS to enable them to properly detect the SRS for position determination.

[0024]

[0029] For a given frequency, the serving base station 110-1 may configure the UE 120 by performing time-domain division (TDD) resource designation using different layers to perform different functions. As described herein, the “higher layers” may comprise layers at which the serving base station 110-1 provides control information to the UE 120 via a radio resource control (RRC) protocol (e.g., an RRC layer). The higher layers may further include an application layer, a media access control (MAC) layer, or other layers that can provide the UE 120 with designated times for SRS signaling. Furthermore, the “lower layers” may comprise a physical layer having a scheduler that can provide downlink control information (DCI) (e.g., transport format, resource allocation, etc.) to the UE 120 via a physical downlink control channel (PDCCH). The higher layers of the serving base station 110-1 may perform semi-static designation of time-domain resource elements using RRC signaling to implement cell-specific and / or UE-specific patterns. (The frequency with which these designations may occur may be on the order of a few milliseconds to a few hundred milliseconds.) Lower layers of the serving base station 110-1 may implement dynamic designation of time domain resources per slot (e.g., with much finer granularity than RRC signaling) using a slot format indicator (SFI) in the DCI. The SFI comprises an index reference into a table that indicates the designation for a particular symbol within the slot.

[0025]

[0030] The different designations that form these patterns comprise DL, UL, flexible, and reserved. The DL and UL designations indicate resources for DL ​​and UL communication, respectively. Thus, the UE 120 can listen to and decode information communicated using DL-designated resources and similarly transmit data using UL-designated resources. Reserved resources are "no transmit" and "no receive" resources that the UE 120 cannot use to transmit or receive data. Resources designated as flexible are neither UL nor DL ​​resources, but may be designated as such through dynamic designation in the DCI at lower layers. Unless overridden in this manner, the flexible designation has traditionally been used to achieve the same as the reserved designation.

[0026]

[0031] However, according to embodiments herein, UE 120 may be configured to transmit the positioning SRS on one or more symbols of a slot designated as flexible, thereby efficiently transmitting the positioning SRS without waiting for UL-designated resources to do so, possibly using unused time resources. In such cases, UE 120 may be configured by higher layers of serving base station 110-1 (e.g., via an RRC configuration message) to transmit the positioning SRS. For a given slot, if lower layers of serving base station 110-1 designate one or more symbols as flexible, the UE may transmit the positioning SRS on at least a portion of one or more symbols. Additional details are provided in FIG. 3.

[0027]

[0032] 3 is a call flow diagram illustrating a method of SRS transmission for positioning, according to one embodiment. However, it may be noted that alternative embodiments may vary in functionality by combining, separating, or otherwise varying the functions described in the blocks shown in FIG. 3 and / or the information communicated in the arrows shown in FIG. 3.

[0028]

[0033] The method may begin at arrow 310, where serving base station 110-1 sends an upper layer configuration message to UE 120. As mentioned, this upper layer configuration message may comprise an RRC message or a similar message provided by the RRC layer, which may identify slots in which UE 120 is to transmit the positioning SRS, including a set of symbols within the slots in which the positioning SRS may be transmitted. In upper layer configuration 310, serving base station 110-1 may provide additional types of configuration, such as cell-specific RRC configuration and / or UE-specific RRC configuration, which may establish semi-static indication as described above. The semi-static indication may be activated and deactivated via a MAC control element (MAC-CE), as indicated by arrow 315 in FIG. 3 (which shows an optional activation message for cases in which semi-static indication is used). (However, it may be noted that this activation message may come at any time prior to the positioning SRS and not necessarily after the function shown in block 340.) Higher layers may similarly establish a periodic indication via RRC configuration, in which case it is activated after a fixed delay upon receipt of the message.

[0029]

[0034] Serving base station 110-1 may distinguish a positioning SRS from other types of SRS. That is, serving base station 110-1 may provide information to UE 120 indicating that the SRS will be used for positioning. In the case of an SRS flagged as a positioning SRS, UE 120 may therefore determine (as shown in block 320 of FIG. 3) that the SRS will be used for positioning and, therefore, determine that the SRS may be transmitted on symbols designated as flexible. (If not designated as a positioning SRS, UE 120 may refrain from transmitting the SRS on flexible symbols and instead transmit only on UL symbols.) It may be noted that in some cases and / or embodiments, the determination that the SRS will be used for positioning (in block 320) does not necessarily have to be made before lower layer configuration 330 is sent from serving base station 110-1.

[0030]

[0035] Using the lower layer configuration 330 (e.g., DCI), serving base station 110-1 can provide, via the PDCCH, dynamic indication to UE 120 of the slots identified in the higher layer configuration 310, as well as other configuration information. As mentioned, the dynamic indication can be provided using an SFI, which can specify a subset of symbols identified as flexible in the higher layer configuration.

[0031]

[0036] For its part, the UE 120 can then identify symbols for slots designated for SRS transmission that are designated as flexible by the SFI in the lower layer configuration at 340. Finally, as shown by arrow 350, the UE 120 can transmit at least a portion of the positioning SRS using one or more of the symbols designated as flexible by the SFI. As noted, by doing so, the UE can utilize potentially unused flexible resources. This can enable the UE 120 to provide SRS more frequently and allow the terrestrial positioning system 100 to make more SRS measurements. This can increase the accuracy of positioning and tracking the UE 120.

[0032]

[0037] FIG. 4 is a flow diagram of a method 400 for transmitting a reference signal for positioning, according to one embodiment. The method 400 may be performed by a UE (e.g., the UE 120) and may correspond to the functionality of the UE 120 shown in FIG. 3. As with the other figures provided herein, FIG. 4 is provided as a non-limiting example. Alternative embodiments may vary in functionality by combining, separating, or otherwise varying the functionality described in the blocks shown in FIG. 4. Means for performing the functionality of one or more of the blocks shown in FIG. 4 may comprise hardware and / or software components of a UE, such as the UE 120 shown in FIG. 4 and described in more detail below. Furthermore, it may be noted that the functionality shown in FIG. 4 may be performed by a UE for transmission of a positioning SRS signal for any purpose, including for UL-only positioning and / or UL+DL positioning.

[0033]

[0038] In block 410, the function comprises receiving a message from a serving base station comprising instructions to transmit an SRS on a set of symbols of an OFDM slot, where the set of symbols may comprise all or a portion of the symbols in the slot. Further, as mentioned above, the message may comprise an upper layer configuration message from the serving base station, such as an RRC message. Moreover, the message may be provided periodically to configure the UE, which may establish a cell-specific RRC configuration and / or a UE-specific RRC configuration. Means for performing the function in block 410 may include one or more software and / or hardware components of the UE, such as the bus 405, processing unit(s) 410, memory 460, wireless communication interface 430, and / or other software and / or hardware components of the UE 120, as shown in FIG. 4 and described in more detail below.

[0034]

[0039] At block 420, the function optionally comprises determining an SRS to be used for positioning. As shown in the embodiments described above, this may be done in any of a variety of manners. In some embodiments, for example, a positioning designation of the SRS may be provided in an RRC message (e.g., the message received at block 410). In such cases, a specific IE in the RRC may provide this designation. In some embodiments, determining the SRS to be used for positioning may comprise determining that the SRS is to be transmitted as part of a multi-RTT positioning session, UL-TDOA position determination, UL-AoA position determination, or any combination thereof. Additionally or alternatively, in some embodiments, determining the SRS to be used for positioning may comprise determining that the SRS is associated with a non-serving base station (e.g., a neighboring base station). In some embodiments, determining that the SRS should be used for positioning comprises determining that the SRS comprises a DL positioning reference signal (PRS), which may be used not only for multi-RTT but also for other types of positioning, such as UL AoA, RSRP, etc. This may mean, for example, that the serving base station provides the UE with the configuration of the SRS and DL PRS in the same message. Whether the SRS is to be used as part of a particular position determination, positioning session, etc., or is associated with another base station may be provided to the UE 120 via an entity that coordinates positioning determinations, such as location server 130. Means for performing the functions in block 420 may include one or more software and / or hardware components of the UE, such as bus 405, processing unit(s) 410, memory 460, and / or other software and / or hardware components of the UE 120, as shown in FIG. 4 and described in more detail below.

[0035]

[0040] In block 430, the function comprises receiving, from the serving base station, a DCI with an SFI that designates a subset of the set of symbols as flexible. As mentioned, the relevant 3GPP standards allow symbols of a slot to be designated as UL, DL, flexible, or reserved. Furthermore, lower layers may use the SFI to redesignate flexible symbols as UL or DL. However, if left as flexible under the SFI, the UE can utilize them for SRS transmission, as described herein. Means for performing the function in block 430 may include one or more software and / or hardware components of the UE, such as the bus 405, processing unit(s) 410, memory 460, wireless communication interface 430, and / or other software and / or hardware components of the UE 120, as shown in FIG. 4 and described in more detail below.

[0036]

[0041] In block 440, the function comprises transmitting the SRS on at least a portion of the subset. In some instances, for example, the UE may transmit the SRS on one of a number of symbols designated as flexible by the SFI, which comprises a subset of symbols designated for transmitting positioning SRS by higher layers of the serving base station.

[0037]

[0042] Furthermore, in some embodiments, transmitting the SRS may be further based on receiving an indication from the serving base station that transmitting the SRS on flexible symbols is permissible. That is, embodiments may "turn on" this feature as needed. As noted above, this may be done using an IE in an RRC message from the base station (which may be the same or a different message as the message sent in block 410). Additionally or alternatively, this may be done using a MAC-CE from the serving base station. (This may be included, for example, in the activation message 315 of FIG. 3 or in a separate MAC-CE.)

[0043] In some embodiments, this feature may be adopted based on a particular version of the relevant 3GPP standard, and thus, the UE may implement this feature based on a determination that the serving base station supports a particular version of that standard. In particular, this feature may be incorporated into Release 16 or 17 of 3GPP specification TS 28.213. Thus, if the UE determines that the serving base station supports Release 16, 17 (or higher), this feature may be implemented. This determination may be based on information received from the serving base station and / or location server (which may include, e.g., upper layer configuration 310, lower layer configuration 330, and / or activation message 315 of FIG. 3). In some embodiments, for example, one or more information elements (IEs) in upper layer configuration 310 may provide this information (e.g., SRS-PosResourceSet-r16).

[0038]

[0044] The means for performing the functions in block 440 may include one or more software and / or hardware components of the UE, such as the bus 405, processing unit(s) 410, memory 460, wireless communication interface 430, and / or other software and / or hardware components of the UE 120, as shown in FIG. 4 and described in more detail below.

[0039]

[0045] FIG. 5 illustrates one embodiment of a UE 120 that may be utilized as described above in this specification (e.g., in connection with FIGS. 1-5). For example, the UE 120 may perform one or more of the functions of the method 400 of FIG. 4. It should be noted that FIG. 5 merely provides a generalized view of various components, any or all of which may be utilized as appropriate. It should be noted that in some instances, the components illustrated by FIG. 5 may be localized in a single physical device and / or distributed among various networked devices that may be disposed in different physical locations. Furthermore, similar to the serving base station described herein, the UE may comprise various layers (e.g., a physical layer, a MAC layer, an IP layer, an application layer, etc.), which may be performed by one or more of the hardware and / or software components illustrated in FIG. 5.

[0040]

[0046] The UE 120 is shown comprising hardware elements that may be electrically coupled (or in other communication, as appropriate) via a bus 505. The hardware elements may include processing unit(s) 510, which may include, but are not limited to, one or more general-purpose processors, one or more special-purpose processors (such as digital signal processing (DSP) chips, graphics acceleration processors, application-specific integrated circuits (ASICs)), and / or other processing structures or means. As shown in FIG. 5, some embodiments may have a separate digital signal processor (DSP) 520 depending on desired functionality. Location determination and / or other determinations based on wireless communications may be provided in the processing unit(s) 510 and / or in a wireless communications interface 530 (described below). The UE 120 also may include one or more input devices 570, which may include, but are not limited to, a keyboard, a touchscreen, a touchpad, a microphone, button(s), dial(s), switch(es), etc., and one or more output devices 515, which may include, but are not limited to, a display, a light-emitting diode (LED), a speaker, etc.

[0041]

[0047] The UE 120 may also include a wireless communication interface 530, which may comprise, but is not limited to, a modem, network card, infrared communication device, wireless communication device, and / or chipset (such as a Bluetooth device, an IEEE 802.11 device, an IEEE 802.15.4 device, a Wi-Fi device, a WiMAX device, a WAN device, and / or various cellular devices), which may enable the UE 120 to communicate with other devices as described in the above embodiments. The wireless communication interface 530 may enable data and signaling to be communicated (e.g., transmitted and received) with a network, for example, via an eNB, a gNB, an ng-eNB, an access point, various base stations and / or other access node types, and / or other network components, a computer system, and / or any other electronic device described herein. Communication may occur via one or more wireless communication antennas 532 that send and / or receive wireless signals 534. According to some embodiments, the wireless communication antenna(s) 532 may comprise multiple individual antennas, an antenna array, or any combination thereof.

[0042]

[0048] Depending on desired functionality, the wireless communication interface 530 may comprise separate receivers and transmitters, or any combination of transceivers, transmitters, and / or receivers, for communicating with other terrestrial transceivers, such as base stations (e.g., ng-eNBs and gNBs), as well as wireless devices and access points. The UE 120 may communicate with different data networks, which may comprise a variety of network types. For example, a wireless wide area network (WWAN) may be a CDMA network, a time division multiple access (TDMA) network, a frequency division multiple access (FDMA) network, an orthogonal frequency division multiple access (OFDMA) network, a single-carrier frequency division multiple access (SC-FDMA) network, a WiMAX (IEEE 802.16) network, etc. A CDMA network may implement one or more radio access technologies (RATs), such as CDMA2000, WCDMA, etc. cdma2000 includes IS-95, IS-2000, and / or IS-856 standards. A TDMA network may implement GSM, Digital Advanced Mobile Phone System (D-AMPS), or some other RAT. An OFDMA network may employ LTE, LTE Advanced, 5G NR, etc. 5G NR, LTE, LTE Advanced, GSM, and WCDMA are described in documents from the 3rd Generation Partnership Project (3GPP). cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). 3GPP and 3GPP2 documents are publicly available. A wireless local area network (WLAN) may also be an IEEE 802.11x network, and a wireless personal area network (WPAN) may be a Bluetooth network, an IEEE 802.15x, or some other type of network. Also, the techniques described herein may be used for any combination of WWAN, WLAN, and / or WPAN.

[0043]

[0049] The UE 120 may further include sensor(s) 540. The sensors 540 may comprise, but are not limited to, one or more inertial sensors and / or other sensors (e.g., accelerometer(s), gyroscope(s), camera(s), magnetometer(s), altimeter(s), microphone(s), proximity sensor(s), light sensor(s), barometer(s), etc.), some of which, in some instances, may be used to supplement and / or facilitate the position determination described herein.

[0044]

[0050] An embodiment of UE 120 may also include a global navigation satellite system (GNSS) receiver 580 capable of receiving signals 584 from one or more GNSS satellites using an antenna 582 (which may be the same as antenna 532). Positioning based on GNSS signal measurements may be utilized to complement and / or incorporate the techniques described herein. GNSS receiver 580 may extract the position of UE 120 using conventional techniques from GNSS SVs of a GNSS system, such as Global Positioning System (GPS), Galileo, GLONASS, Japan's Quasi-Zenith Satellite System (QZSS), India's Indian Regional Navigation Satellite System (IRNSS), or China's Beidou. Moreover, the GNSS receiver 580 may be used with various augmentation systems (e.g., Satellite Based Augmentation System (SBAS)) that may be associated with or otherwise enabled for use with one or more global and / or regional navigation satellite systems, such as, for example, WAAS, EGNOS, Multi-functional Satellite Augmentation System (MSAS), and Geo Augmented Navigation system (GAGAN).

[0045]

[0051] The UE 120 may further include and / or be in communication with memory 560. The memory 560 may include, but is not limited to, local and / or network-accessible storage, disk drives, drive arrays, optical storage devices, and solid-state storage devices such as random access memory (RAM) and / or read-only memory (ROM), which may be programmable, flash-updateable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc.

[0046]

[0052] The memory 560 of the UE 120 may also comprise computer programs provided by various embodiments and / or may comprise software elements (not shown in FIG. 5 ) including other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, that may be designed to implement methods and / or configure systems provided by other embodiments as described herein. By way of example only, one or more procedures described with respect to the method(s) described above may be implemented as code and / or instructions in the memory 560 that are executable by the UE 120 (and / or processing unit(s) 510 or DSP 520 within the UE 120). In one aspect, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the described method.

[0047]

[0053] FIG. 6 illustrates one embodiment of a base station 110 that may be utilized as described above in this specification (e.g., in connection with FIGS. 1-5). Note that FIG. 6 merely provides a generalized view of various components, any or all of which may be utilized as appropriate. In some embodiments, the base station 110 may correspond to a gNB, an ng-eNB, and / or an eNB. As mentioned, the base station 110 may comprise various layers (e.g., a physical layer, a MAC layer, an IP layer, an application layer, etc.), which may be performed by one or more of the hardware and / or software components illustrated in FIG. 6.

[0048]

[0054] The base station 110 is shown comprising hardware elements that may be electrically coupled (or in other communication, as appropriate) via a bus 605. The hardware elements may include processing unit(s) 610, which may include, but are not limited to, one or more general-purpose processors, one or more special-purpose processors (such as DSP chips, graphics acceleration processors, ASICs, etc.), and / or other processing structures or means. As shown in FIG. 6, some embodiments may have a separate DSP 620 depending on the desired functionality. Location determination and / or other determinations based on wireless communications may be provided in the processing unit(s) 610 and / or in a wireless communications interface 630 (described below), according to some embodiments. The base station 110 may also include one or more input devices, which may include, but are not limited to, a keyboard, a display, a mouse, a microphone, button(s), dial(s), switch(es), etc., and one or more output devices, which may include, but are not limited to, a display, a light-emitting diode (LED), a speaker, etc.

[0049]

[0055] The base station 110 may also include a wireless communication interface 630, which may comprise, but is not limited to, a modem (such as a Bluetooth device, an IEEE 802.11 device, an IEEE 802.15.4 device, a Wi-Fi device, a WiMAX device, cellular communication equipment), a network card, an infrared communication device, a wireless communication device, and / or a chipset, etc., which may enable the base station 110 to communicate as described herein. The wireless communication interface 630 may enable data and signaling to be communicated (e.g., transmitted and received) with UEs, other base stations (e.g., eNBs, gNBs, and ng-eNBs), and / or other network components, computer systems, and / or any other electronic devices described herein. Communication may occur via one or more wireless communication antennas 632 that send and / or receive wireless signals 634.

[0050]

[0056] The base station 110 may also include a network interface 680, which may include support for wireline communication technologies. The network interface 680 may include a modem, a network card, a chipset, etc. The network interface 680 may include one or more input and / or output communication interfaces to allow data to be exchanged with networks, communication network servers, computer systems, and / or any other electronic devices described herein.

[0051]

[0057] In many embodiments, base station 110 may further comprise memory 660. Memory 660 may include, but is not limited to, local and / or network-accessible storage, disk drives, drive arrays, optical storage devices, and solid-state storage devices such as RAM and / or ROM, which may be programmable, flash-updateable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc.

[0052]

[0058] The memory 660 of the base station 110 may also comprise computer programs provided by various embodiments and / or may comprise software elements (not shown in FIG. 6 ) including other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, that may be designed to implement methods and / or configure systems provided by other embodiments, as described herein. By way of example only, one or more procedures described with respect to the method(s) described above may be implemented as code and / or instructions in the memory 660 that are executable by the base station 110 (and / or the processing unit(s) 610 or DSP 620 within the base station 110). In one aspect, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the described method.

[0053]

[0059] It will be apparent to those skilled in the art that substantial variations can be made according to particular requirements. For example, customized hardware could also be used, and / or particular elements could be implemented in hardware, software (including portable software such as applets), or both. Furthermore, connection to other computing devices, such as network input / output devices, could be employed.

[0054]

[0060] With reference to the accompanying figures, components that may include memory may include non-transitory machine-readable media. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any storage medium that participates in providing data that causes a machine to operate in a specific manner. In the embodiments provided above, various machine-readable media may participate in providing instructions / code to a processing unit and / or other device(s) for execution. Additionally or alternatively, machine-readable media may be used to store and / or transport such instructions / code. In many implementations, computer-readable media are physical and / or tangible storage media. Such media may take many forms, including, but not limited to, non-volatile media, volatile media, and transmission media. Common forms of computer-readable media include, for example, magnetic and / or optical media, any other physical medium with a pattern of holes, RAM, Programmable ROM (PROM), Erasable PROM (EPROM), FLASH®-EPROM, any other memory chip or cartridge, a carrier wave as described below, or any other medium from which a computer can read instructions and / or code.

[0055]

[0061] The methods, systems, and devices described herein are examples. Various embodiments may omit, substitute, or add various procedures or components, as appropriate. For example, features described with respect to some embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Various components of the diagrams provided herein may be implemented in hardware and / or software. Also, technology evolves, and thus many of the elements are examples, and these examples do not limit the scope of the disclosure to those specific examples.

[0056]

[0062] It has proven convenient at times, principally for reasons of common usage, to refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, numerals, or the like. However, it should be understood that all of these or similar terms are to be associated with the appropriate physical quantities and are merely convenient labels. Unless otherwise indicated, and as is clear from the above description, it should be appreciated that throughout this specification, descriptions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” “ascertaining,” “identifying,” “associating,” “measuring,” “performing,” and the like refer to actions or processes of a particular apparatus, such as a special purpose computer or similar special purpose electronic computing device. Thus, in the context of this specification, a special purpose computer or similar special purpose electronic computing device is capable of manipulating or transforming signals that are generally represented as electronic, electrical, or magnetic physical quantities within memories, registers, or other information storage, transmission, or display devices of the special purpose computer or similar special purpose electronic computing device.

[0057]

[0063] The terms "and" and "or" as used herein may have a variety of meanings that are expected to depend, at least in part, on the context in which such terms are used. In general, when "or" is used to associate a list, such as A, B, or C, it shall mean A, B, and C, used herein in an inclusive sense, as well as A, B, or C, used herein in an exclusive sense. Furthermore, as used herein, the term "one or more" may be used to describe any feature, structure, or characteristic in the singular, or it may be used to describe any combination of features, structures, or characteristics. However, it should be noted that this is an illustrative example only, and claimed subject matter is not limited to this example. Furthermore, the term "at least one of," when used to associate a list, such as A, B, or C, may be interpreted to mean any combination of A, B, and / or C, such as A, AB, AA, AAB, AABBCCC, etc.

[0058]

[0064] Although several embodiments have been described, various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the present disclosure. For example, the above elements may be merely components of a larger system, and other rules may take precedence over or otherwise modify the application of the various embodiments. Also, some steps may be taken before, during, or after the above elements are considered. Therefore, the above description does not limit the scope of the present disclosure.

[0059]

[0065] In view of this description, embodiments may include different combinations of features. Example implementations are described in the following numbered clauses. Clause 1. A method in a user equipment (UE) for transmitting a reference signal for positioning, the method comprising: receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receiving, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; and transmitting the SRS for positioning on at least a portion of the subset. Clause 2. The method of clause 1, wherein the message comprises a radio resource control (RRC) message. Clause 3. The method of clause 1 or 2, further comprising determining that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message. Clause 4. The method of any of clauses 1 to 3, wherein the positioning specification comprises an information element (IE) in an RRC message. Clause 5. The method of any of clauses 1 to 4, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS should be transmitted as part of a multi-RTT positioning session, an uplink time difference of arrival (UL-TDOA) position determination, an uplink angle of arrival (UL-AoA) position determination, or any combination thereof. Clause 6. The method of any of clauses 1 to 4, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS comprises a downlink (DL) positioning reference signal (PRS). Clause 7. The method of any of clauses 1 to 4, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS is associated with a non-serving base station. Clause 8. The method of any of clauses 1 to 7, wherein transmitting the SRS is further based on receiving an indication from the serving base station that transmitting the SRS on flexible symbols is acceptable. Clause 9. The method of any of clauses 1 to 8, wherein transmitting the SRS is further based on receiving an indication that the serving base station supports a version of the data communications standard in which transmitting the SRS on flexible symbols is acceptable. Clause 10. The method of clause 9, wherein the indication that transmitting the SRS on the flexible symbol is permissible is conveyed using an IE in the second message received from the serving base station. Clause 11. The method of clause 9, wherein the indication that it is permissible to transmit the SRS on the flexible symbol is conveyed from the serving base station using a media access control (MAC) control element (MAC-CE). Clause 12. A mobile device comprising a wireless transceiver, a memory, and one or more processing units communicatively coupled to the wireless transceiver and the memory, the one or more processing units configured to: receive, from a serving base station, via the wireless transceiver, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receive, from the serving base station, via the wireless transceiver, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; and transmit, via the wireless transceiver, the SRS for positioning on at least a portion of the subset. Clause 13. The mobile device of clause 12, wherein to receive the message, the one or more processing units are configured to receive a radio resource control (RRC) message. Clause 14. The mobile device of clause 12 or 13, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message. Clause 15. The mobile device of any of clauses 12 to 14, wherein the one or more processing units are configured to identify an information element (IE) in the RRC message to identify a positioning designation of the SRS in the RRC message. Clause 16. The mobile device of any of clauses 12 to 15, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on determining that the SRS should be transmitted as part of a multi-RTT positioning session, an uplink time difference of arrival (UL-TDOA) position determination, an uplink angle of arrival (UL-AoA) position determination, or any combination thereof. Clause 17. The mobile device of any of clauses 12 to 15, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on determining that the SRS comprises a downlink (DL) positioning reference signal (PRS). Clause 18. A mobile device according to any of clauses 12 to 15, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on determining that the SRS is associated with a non-serving base station. Clause 19. The mobile device of any of clauses 12 to 18, wherein the one or more processing units are configured to transmit the SRS further based on receiving, from a serving base station, via the wireless transceiver, an indication that transmitting the SRS on flexible symbols is acceptable. Clause 20. The mobile device of any of clauses 12 to 19, wherein the one or more processing units are configured to transmit the SRS further based on receiving, via the wireless transceiver, an indication that the serving base station supports a version of the data communications standard in which transmitting the SRS over flexible symbols is acceptable. Clause 21. The mobile device of clause 20, wherein the one or more processing units are configured to receive an indication from the serving base station via a media access control (MAC) control element (MAC-CE) that transmitting SRS over flexible symbols is permissible. Clause 23. A device comprising: means for receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; means for receiving, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; and means for transmitting an SRS for positioning on at least a portion of the subset. Clause 24. The device of clause 23, wherein the means for receiving a message comprises means for receiving a radio resource control (RRC) message, and further comprises means for determining that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message. Clause 25. The device of clause 23 or 24, wherein the means for identifying a positioning designation comprises means for identifying an information element (IE) in an RRC message. Clause 26. The device of any of clauses 23 to 25, further comprising means for determining that the SRS should be used for positioning based at least in part on determining that the SRS should be transmitted as part of a multi-RTT positioning session, an uplink time difference of arrival (UL-TDOA) position determination, an uplink angle of arrival (UL-AoA) position determination, or any combination thereof. Clause 27. The device of any of clauses 23 to 26, further comprising: means for determining that the SRS should be used for positioning based at least in part on determining that the SRS comprises a downlink (DL) positioning reference signal (PRS).Clause 28. The device of any of clauses 23 to 26, further comprising: means for determining that the SRS should be used for positioning based at least in part on determining that the SRS is associated with a non-serving base station. Clause 29. A non-transitory computer-readable medium storing instructions for transmitting a reference signal for positioning, the instructions comprising: code for receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receiving, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; and transmitting the SRS for positioning on at least a portion of the subset. Clause 30. The non-transitory computer-readable medium of clause 29, wherein the code for receiving the message comprises code for receiving a radio resource control (RRC) message, and further comprises code for determining that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message.

Claims

1. 1. A method in a user equipment (UE) for transmitting a reference signal for positioning, the method comprising: receiving a message from a serving base station comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receiving downlink control information (DCI) from the serving base station having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; transmitting the SRS for positioning on at least a portion of the subset; A method comprising:

2. The method of claim 1 , wherein the message comprises a radio resource control (RRC) message.

3. 3. The method of claim 2, further comprising determining that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message.

4. The method of claim 3 , wherein the positioning specification comprises an information element (IE) in the RRC message.

5. The SRS is Multi-RTT positioning session, Uplink Time Difference of Arrival (UL-TDOA) positioning; Uplink Angle of Arrival (UL-AoA) positioning; or any combination thereof 10. The method of claim 1, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS should be transmitted as part of a time domain signal.

6. 10. The method of claim 1, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS comprises a downlink (DL) positioning reference signal (PRS).

7. The method of claim 1 , further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS is associated with a non-serving base station.

8. The method of claim 1 , wherein transmitting the SRS is further based on receiving an indication from the serving base station that transmitting the SRS on a flexible symbol is permissible.

9. 10. The method of claim 1, wherein transmitting the SRS is further based on receiving an indication that the serving base station supports a version of a data communication standard in which transmitting the SRS on a flexible symbol is acceptable.

10. 10. The method of claim 8, wherein the indication that transmitting the SRS on a flexible symbol is permissible is conveyed using an IE in a second message received from the serving base station.

11. 10. The method of claim 8, wherein the indication that transmitting the SRS on a flexible symbol is permissible is conveyed from the serving base station using a medium access control (MAC) control element (MAC-CE).

12. a wireless transceiver; Memory and one or more processing units communicatively coupled to the wireless transceiver and the memory; 1. A mobile device comprising: receiving, via the wireless transceiver, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receiving, via the wireless transceiver, from the serving base station, downlink control information (DCI) having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; transmitting the SRS for positioning on at least a portion of the subset via the wireless transceiver; 1. A mobile device configured to:

13. The mobile device of claim 12 , wherein to receive the message, the one or more processing units are configured to receive a radio resource control (RRC) message.

14. 14. The mobile device of claim 13, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message.

15. 15. The mobile device of claim 14, wherein the one or more processing units are configured to identify an information element (IE) in the RRC message to identify a positioning designation of the SRS in the RRC message.

16. The one or more processing units may further include a processor configured to: Multi-RTT positioning session, Uplink Time Difference of Arrival (UL-TDOA) positioning; Uplink Angle of Arrival (UL-AoA) positioning; or any combination thereof 13. The mobile device of claim 12, configured to determine that the SRS should be used for positioning based at least in part on determining that the SRS should be transmitted as part of a time domain signal.

17. 13. The mobile device of claim 12, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on determining that the SRS comprises a downlink (DL) positioning reference signal (PRS).

18. 13. The mobile device of claim 12, wherein the one or more processing units are configured to determine that the SRS should be used for positioning based at least in part on determining that the SRS is associated with a non-serving base station.

19. 13. The mobile device of claim 12, wherein the one or more processing units are configured to transmit the SRS further based on receiving, from the serving base station, via the wireless transceiver, an indication that transmitting the SRS on a flexible symbol is permissible.

20. 13. The mobile device of claim 12, wherein the one or more processing units are configured to transmit the SRS further based on receiving, via the wireless transceiver, an indication that the serving base station supports a version of a data communication standard in which transmitting the SRS on a flexible symbol is acceptable.

21. 20. The mobile device of claim 19, wherein the one or more processing units are configured to receive the indication that transmitting the SRS on flexible symbols is permissible via an IE in a second message received from the serving base station.

22. 20. The mobile device of claim 19, wherein the one or more processing units are configured to receive the indication from the serving base station via a medium access control (MAC) control element (MAC-CE) that transmitting the SRS on a flexible symbol is permissible.

23. means for receiving, from a serving base station, a message comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; means for receiving downlink control information (DCI) from the serving base station having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; means for transmitting the SRS for positioning on at least a portion of the subset; A device comprising:

24. 24. The device of claim 23, wherein the means for receiving the message comprises means for receiving a Radio Resource Control (RRC) message, and further comprises means for determining that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message.

25. 25. The device of claim 24, wherein the means for identifying the positioning designation comprises means for identifying an information element (IE) in the RRC message.

26. The SRS is Multi-RTT positioning session, Uplink Time Difference of Arrival (UL-TDOA) positioning; Uplink Angle of Arrival (UL-AoA) positioning; or any combination thereof 24. The device of claim 23, further comprising: means for determining that the SRS should be used for positioning based at least in part on determining that the SRS should be transmitted as part of a time domain signal.

27. 24. The device of claim 23, further comprising: means for determining that the SRS should be used for positioning based at least in part on determining that the SRS comprises a downlink (DL) positioning reference signal (PRS).

28. 24. The device of claim 23, further comprising: means for determining that the SRS should be used for positioning based at least in part on determining that the SRS is associated with a non-serving base station.

29. 1. A non-transitory computer-readable medium storing instructions for transmitting a reference signal for positioning, the instructions comprising: receiving a message from a serving base station comprising instructions to transmit a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receiving downlink control information (DCI) from the serving base station having a slot format indicator (SFI) that designates a subset of the set of symbols as flexible; transmitting the SRS for positioning on at least a portion of the subset; 12. A non-transitory computer-readable medium comprising code for performing

30. 30. The non-transitory computer-readable medium of claim 29, wherein the code for receiving the message comprises code for receiving a Radio Resource Control (RRC) message, and further comprises code for determining that the SRS should be used for positioning based at least in part on identifying a positioning designation of the SRS in the RRC message.

Images