Sounding Reference Signal (SRS) Transmission for Positioning on Flexible Symbols

Abstract

Sounding reference signal (SRS) transmission for positioning may be utilized on flexible symbols. Disclosed techniques for transmitting a reference signal for positioning comprise receiving, from a serving base station, a message comprising instructions to transmit the SRS on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot. The techniques may also comprise determining that the SRS should be used for positioning and 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 techniques may also comprise transmitting the SRS on at least a portion of the subset.

Description

Technical Field

[0001]

[0001] The present invention generally relates to the field of wireless communication, and more particularly to determining the location or position of a mobile electronic device in a wireless communication network.

Background Art

[0002]

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

Summary of the Invention

[0003]

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

[0004]

[0004] An exemplary mobile device according to the present disclosure includes 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 an instruction 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 specifies a subset of the set of symbols as flexible. The one or more processing units are also configured to transmit, via the wireless transceiver, an SRS for positioning on at least a portion of the subset.

[0005]

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

[0006]

[0006] An exemplary non - transitory computer - readable medium according to the present disclosure stores instructions that include code for transmitting a reference signal for positioning. The instructions also include code for receiving, from a serving base station, a message comprising an instruction for transmitting a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency - division multiplexing (OFDM) slot. The instructions also include 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 include code for transmitting an SRS for positioning on at least a portion of the subset.

Brief Description of the Drawings

[0007]

Figure 1

[0007] A diagram of a terrestrial positioning system according to one embodiment.

Figure 2

[0008] A diagram showing an example of a frame structure that can be used in wireless communication in the positioning system of FIG. 1 according to one embodiment.

Figure 3

[0009] A call - flow diagram showing a method for transmitting a sounding reference signal (SRS) for positioning according to one embodiment.

Figure 4

[0010] A flowchart of a method for transmitting a reference signal for positioning according to one embodiment.

Figure 5

[0011] A block diagram of one embodiment of a user equipment (UE) that can be utilized as described herein.

Figure 6

[0012] A block diagram of one embodiment of a base station that can be utilized as described herein.

Modes for Carrying Out the Invention

[0008]

[0013] Like reference symbols in the various drawings indicate like elements in accordance with some exemplary implementations. Further, multiple instances of an element may be indicated by following the first number for the element with 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 is to be understood (e.g., element 110 in the previous example refers to element 110-1, 110-2, and 110-3, or to element 110a, 110b, and 110c).

[0009]

[0014] Next, some exemplary embodiments with respect to the accompanying drawings that form a part of this application are described. Specific embodiments in which one or more aspects of the present disclosure may be implemented are described below, but 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, "RF signal" or "wireless signal" comprises an electromagnetic wave that transports information through the space between a transmitter or transmitting device and a receiver or receiving device. A transmitter as used herein may transmit one or more RF / wireless signals to a receiver. As will be described in more detail herein, an RF / wireless signal may comprise an uplink (UL) signal and / or a downlink (DL) signal that 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, the receiver may receive a corresponding plurality of 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 the receiver may be referred to as a "multipath" RF signal.

[0011]

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

[0012]

[0017] FIG. 1 provides a generalized view of various components, noting that any or all of those components may be utilized as appropriate and each of those components may be replicated or omitted as needed. Specifically, although 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 that communicatively connect the various components in the terrestrial positioning system 100 may include additional (intermediate) components, direct or indirect physical (wired) and / or wireless connections, and / or additional networks, including data and signaling connections. Further, the components may be rearranged, combined, separated, replaced, 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 that 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 DL-only positioning methods, UL-only positioning methods, and / or DL+UL positioning methods), the more accurate the positioning of the UE 120 will be.

[0013]

[0018] The UE120 used in this specification can be an electronic device and may be referred to as a device, mobile device, wireless device, mobile terminal, terminal, wireless terminal, mobile station (MS), secure user plane location (SUPL)-enabled terminal (SET), or by some other name. Moreover, the UE120 can correspond to a cell phone, smartphone, laptop, tablet, personal digital assistant (PDA), tracking device, wearable device, internet of things (IOT) device, or some other portable or mobile device. In some cases, the UE120 can be part of some other entity, for example, a chipset that supports a modem incorporated into some larger mobile entity such as a vehicle, drone, package, transportation, robotic device, etc. As described, the UE120 can support wireless communication under the 5G NR standard. However, the UE120 can support wireless communication using one or more additional radio access technologies (RATs) such as the global system for mobile communications (GSM (registered trademark)), code division multiple access (CDMA), wideband CDMA (WCDMA (registered trademark)), long term evolution (LTE (registered trademark)), high rate packet data (HRPD), IEEE802.11 Wi-Fi (registered trademark), Bluetooth (registered trademark) (BT), worldwide interoperability for microwave access (WiMAX (registered trademark)), etc. The UE120 can also support wireless communication using a wireless local area network (WLAN) that can connect to other networks (such as the internet) using, for example, digital subscriber line (DSL) or packet cable. Further, the embodiments provided in this specification are targeted at SRS transmission by the UE120 under 5G NR, although alternative embodiments can be extended to other forms of wireless communication.

[0014]

[0019] UE120 may include a single entity or may include multiple entities, such as in a personal area network where the user may employ audio, video and / or data I / O devices and / or body sensors and separate wireline or wireless modems. The estimated value of the location of UE120 may be referred to as location, location estimate, location fix, fix, position, position estimate or position fix, and may be geodesic and thus may or may not include an altitude component (e.g., altitude above sea level, surface altitude or surface depth, floor level or storey level) and may provide the location coordinates (e.g., latitude and longitude) of UE120. Alternatively, the location of UE120 may be represented as an urban location (e.g., as a postal address or as the designation of some point or small area within a building, such as a particular room or floor). The location of UE120 may also be represented as an area or volume within which UE120 is expected to be located (defined either geodesically or in an urban form) with a certain probability or level of confidence (e.g., 67%, 95%, etc.). The location of UE120 may further be a relative location with distance and direction or relative X, Y (and optionally Z) coordinates defined relative to some origin at a known location defined, for example, by reference to a point, area or volume shown on a geodesic, urban, or map, floor plan, or building plan. In the descriptions contained herein, the use of the term location may, unless otherwise specified, encompass any of these variations. When calculating the location of a UE, it is common to determine the values of local X, Y, and optionally Z coordinates and then, if necessary, convert the local coordinates to absolute coordinates (e.g., relative to latitude, longitude, and altitude above or below mean sea level).

[0015]

[0020] Depending on the desired functionality, WAN140 may comprise any of a variety of wireless and / or wireline communication networks. WAN140 can comprise any combination, for example, of public and / or private networks, local and / or wide area networks, etc. Further, WAN140 may utilize one or more wired communication technologies and / or wireless communication technologies (such as one or more of the aforementioned wireless communication technologies). In some embodiments, WAN140 may comprise, for example, a cellular or other mobile network, a WLAN, a wireless wide area network (WWAN), and / or the Internet.

[0016]

[0021] Base station 110 may comprise a node of WAN140 (or otherwise communicatively coupled to WAN140) that enables UE120 to wirelessly communicate with other devices linked to WAN140. The location of UE120 can be further determined using wireless signal 150 (as described in more detail below) and the known location of base station 110. It may be further noted that the technique is not necessarily limited to fixed base stations (i.e., base stations having a fixed location), but may also include mobile base stations. In a 5G NR network (e.g., when WAN140 comprises a wireless data network supporting 5G NR communication), each base station 110 may comprise a transmission and reception point (TRP), such as an NR node B (gNB) and / or an antenna of the gNB. Additionally or alternatively, base station 110 may comprise a node B, an evolved node B (eNodeB or eNB), a base transceiver station (BTS), a radio base station (RBS), or a next-generation eNB (ng-eNB). Thus, UE120 can send and receive information regarding network-connected devices, such as location server 130, by accessing WAN140.

[0017]

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

[0018]

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

[0019]

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

[0020]

[0025] FIG. 2 is a diagram showing an example of a frame structure for NR and related terms that can serve as a basis for physical layer communication between the UE 120 and a base station 110 such as the serving base station 210-1. The transmission time line for each of the downlink and uplink can be divided into units of radio frames. Each radio frame can have a predetermined duration (e.g., 10 ms) and can be divided into 10 subframes, each of 1 ms, having indexes from 0 to 9. Each subframe can include a variable number of slots depending on the subcarrier spacing. Each slot can include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods in each slot can be assigned indexes. A mini-slot can have a sub-slot structure (e.g., 2, 3, or 4 symbols). Further shown in FIG. 2 is the complete orthogonal frequency division multiplexing (OFDM) of a subframe showing how a subframe can be divided into a plurality of resource blocks (RBs) over both time and frequency. A single RB can comprise a grid of resource elements (REs) over 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 switched dynamically. The link direction may be based on the slot format. Each slot may include DL / UL data as well as 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 2-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 SSS may provide cyclic prefix (CP) length and frame timing. The PSS and SSS may provide cell identification information. The PBCH carries several basic system information, such as downlink system bandwidth, timing information within a radio frame, SS burst set periodicity, system frame number, etc.

[0022]

[0027] As described above, the terrestrial positioning system 100 can use the fact that the positioning technology can include a positioning method of DL only, a positioning method of UL only, or a positioning method of DL+UL to determine the location of the UE 120. For the positioning method of UL only and the positioning method of DL+UL, the UL signal (the signal sent from the UE 120 to the base station 110) can be communicated using symbols in the OFDM slots designated for UL signaling and can include SRS. The 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 the UE 120 and each base station 110 can be determined at least partially based on one or more SRS signals, and the location of the UE 120 can be calculated as the location that satisfies the distance determination given the known locations of the base stations 110. In UL-TDOA, the location of the UE 120 can be calculated similarly based on the difference in the time when the (one or more) SRS signals from the UE 120 are received at different base stations 110 (for example, by comparing the signals received at different pairs of base stations and determining a common solution). In UL-AoA, each base station 110 determines the angle at which the (one or more) SRS signals from the UE 120 are received, and multi-angulation can be used to determine a solution that satisfies the determined angles at each base station 110.

[0023]

[0028] The SRS transmitted by UE120 may comprise a frequency-domain reference signal sequence derived from a Zadoff-Chu sequence. Although it can be used for other purposes, the SRS can be particularly useful for determining the location of UE120 as described above. Under 5G NR, the SRS can be sent periodically, semi-persistently, and / or aperiodically depending on the desired function, and can be configured in any symbol of an NR OFDM slot. Moreover, multi-symbol SRS resources can be staggered in frequency. The serving base station 110-1 may provide UE120 with information on how and when to transmit the SRS, and the location server 130 may notify the neighboring base stations 110-2 and 110-3 of these aspects of the SRS to enable them to appropriately detect the SRS for positioning purposes.

[0024]

[0029] For a given frequency, serving base station 110-1 may configure UE120 by performing time domain division (TDD) resource allocation using different layers to perform different functions. As described herein, the "upper layer" may include a layer through which serving base station 110-1 provides control information to UE120 via a radio resource control (RRC) protocol (e.g., the RRC layer). The upper layer may further include an application layer, a media access control (MAC) layer, or other layers that can provide UE120 with the specified time for SRS signaling. Further, the "lower layer" may include a physical layer having a scheduler that can provide downlink control information (DCI) (e.g., transport format, resource allocation, etc.) to UE120 via a physical downlink control channel (PDCCH). The upper layer of serving base station 110-1 may perform semi-static allocation of time domain resource elements using RRC signaling to implement cell-specific patterns and / or UE-specific patterns. (The frequency at which these allocations can be made can be on the order of several milliseconds to several hundred milliseconds.) The lower layer of serving base station 110-1 may perform dynamic allocation of time domain resources for each slot (e.g., with a much finer granularity than RRC signaling) using the slot format indicator (SFI) in DCI. The SFI comprises an index reference to a table indicating the allocation for specific symbols within the slot.

[0025]

[0030] These different designations for forming these patterns include DL, UL, flexible, and reserved. The DL designation and UL designation indicate resources for their respective DL communications and UL communications. Thus, UE120 can listen for and decode information communicated using the DL-designated resources and, similarly, transmit data using the UL-designated resources. The reserved resources are "do not transmit" and "do not receive" resources that UE120 cannot use to transmit or receive data. The resources designated as flexible are neither UL resources nor DL resources, but can be designated as such through dynamic designation in DCI in the lower layer. If not overwritten in this way, the flexible designation has conventionally been used to achieve the same as the reserved designation.

[0026]

[0031] However, according to the embodiments of this specification, UE120 can be configured to transmit positioning SRS on one or more symbols of a slot designated as flexible, thereby efficiently transmitting the positioning SRS using, in some cases, unused time resources without waiting for UL-designated resources to do so. In such a case, UE120 can be configured to transmit positioning SRS by the upper layer of serving base station 110-1 (e.g., via an RRC configuration message). For a given slot, if the lower layer of serving base station 110-1 designates one or more symbols as flexible, the UE can transmit positioning SRS on at least a portion of the one or more symbols. Additional details are provided in FIG. 3.

[0027]

[0032] FIG. 3 is a call flow diagram showing a method for SRS transmission for positioning according to one embodiment. However, it can be noted that alternative embodiments may vary in function by combining, separating, or otherwise changing 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 can start at arrow 310, where serving base station 110-1 sends a higher layer configuration message to UE 120. As described, this higher layer configuration message may comprise an RRC message provided by the RRC layer or a similar message, which can identify the slot in which the positioning SRS is to be transmitted by UE 120, including the set of symbols within the slot in which the positioning SRS can be transmitted. In higher 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 can establish semi-static indication as described above. The semi-static indication can be activated and deactivated via a MAC control element (MAC-CE), as indicated by arrow 315 in Figure 3 (indicating an optional activation message for the case where semi-static indication is used). (However, it can be noted that this activation message may come at any time before the positioning SRS and not necessarily after the function shown in block 340.) The higher layer may similarly establish a periodic indication via the RRC configuration, in which case it is activated after a fixed delay upon receipt of the message.

[0029]

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

[0030]

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

[0031]

[0036] For that portion, the UE 120 can then, at 340, identify the symbols for the slots designated for SRS transmission that are designated as flexible by the SFI in the lower layer configuration. 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 described, by doing so, the UE can utilize unused flexible resources in some cases. This can enable the UE 120 to provide SRS more frequently and enable the terrestrial positioning system 100 to make more SRS measurements. This can increase the positioning and tracking accuracy of the UE 120.

[0032]

[0037] FIG. 4 is a flowchart of a method 400 for transmitting a reference signal for positioning according to one embodiment. The method 400 may be implemented by a UE (e.g., UE 120) and may correspond to the functions of the UE 120 shown in FIG. 3. Similar to the other figures provided herein, FIG. 4 is provided as a non-limiting example. Alternative embodiments may vary in function by combining, separating, or otherwise changing the functions described in the blocks shown in FIG. 4. The means for performing one or more of the functions shown in the blocks of 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. Further, it may be noted that the functions shown in FIG. 4 may be performed by the UE for any purpose, including for UL-only positioning and / or UL+DL positioning, for the transmission of a positioning SRS signal.

[0033]

[0038] In block 410, the function comprises receiving, from a serving base station, a message comprising an instruction to transmit SRS on a set of symbols of an OFDM slot. Here, the set of symbols may comprise all or a part of the symbols within the slot. Further, as described above, the message may comprise a higher 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 cell-specific RRC configuration and / or UE-specific RRC configuration. Means for implementing the function in block 410 are shown in FIG. 4 and described in more detail below, and may include one or more software and / or hardware components of the UE, such as bus 405 of UE 120, processing unit(s) 410, memory 460, wireless communication interface 430, and / or other software and / or hardware components.

[0034]

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

[0035]

[0040] In block 430, the function comprises receiving, from a serving base station, a DCI having an SFI that specifies a subset of a set of symbols as flexible. As described, the relevant 3GPP standard enables the symbols of a slot to be specified as UL, DL, flexible, or reserved. Moreover, the lower layer may use the SFI to re-specify 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. The means for implementing the function in block 430 are shown in FIG. 4 and described in more detail below, and may include one or more software and / or hardware components of the UE, such as bus 405 of UE 120, (one or more) processing units 410, memory 460, wireless communication interface 430, and / or other software and / or hardware components.

[0036]

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

[0037]

[0042] Further, in some embodiments, transmitting the SRS may further be based on receiving, from the serving base station, an indication that it is acceptable to transmit the SRS on flexible symbols. That is, embodiments may “turn on” this function as needed. As described 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 than 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 function may be adopted based on a particular version of the relevant 3GPP standard, and thus, the UE may implement this function based on a determination that the serving base station supports that particular version of the standard. In particular, this function may be incorporated into Release 16 or 17 of 3GPP specification TS28.213. Thus, if the UE determines that the serving base station supports Release 16, 17 (or higher), this function may be implemented. This determination may be based on information received from the serving base station and / or location server (which may include, for example, the 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 the upper layer configuration 310 may provide this information (e.g., SRS-PosResourceSet-r16).

[0038]

[0044] The means for performing the function in block 440 may include one or more software and / or hardware components of the UE, such as the bus 405 of the UE120, the (one or more) processing units 410, the memory 460, the wireless communication interface 430, and / or other software and / or hardware components, shown in FIG. 4 and described in more detail below.

[0039]

[0045] FIG. 5 shows an embodiment of UE 120 that can be utilized as described above in this specification (e.g., in connection with FIGS. 1-5). For example, UE 120 can implement one or more of the functions of method 400 of FIG. 4. Note that FIG. 5 provides only a generalized diagram of various components, and any or all of those components can be utilized as appropriate. In some cases, it can be noted that the components shown by FIG. 5 can be localized to a single physical device and / or distributed among various networked devices disposed at different physical locations. Further, similar to the serving base station described in this specification, the UE can comprise various layers (physical layer, MAC layer, IP layer, application layer, etc.), which can be executed by one or more of the hardware and / or software components shown in FIG. 5.

[0040]

[0046] UE120 is shown that includes hardware elements that can be electrically coupled via bus 505 (or, optionally, may communicate in other ways). The hardware elements can include, but are not limited to, one or more general-purpose processors, one or more dedicated processors (such as digital signal processing (DSP) chips, graphics acceleration processors, application-specific integrated circuits (ASICs), etc.), and / or other processing structures or means, and can include (one or more) processing units 510. As shown in FIG. 5, some embodiments may have a separate digital signal processor (DSP) 520 depending on the desired functionality. Location determination and / or other determinations based on wireless communication can be provided in (one or more) processing units 510 and / or wireless communication interface 530 (described below). UE120 can also include one or more input devices 570 that can include, but are not limited to, a keyboard, touch screen, touch pad, microphone, (one or more) buttons, (one or more) dials, (one or more) switches, etc., and one or more output devices 515 that can include, but are not limited to, a display, light-emitting diode (LED), speaker, etc.

[0041]

[0047] UE 120 may also include, without limitation, a wireless communication interface 530 that may include, for example, a modem, a network card, an infrared communication device, a wireless communication device, and / or a 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 via, for example, 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. The communication may be performed via one or more wireless communication antennas 532 that send and / or receive wireless signals 534. According to some embodiments, the (one or more) wireless communication antennas 532 may comprise a plurality of individual antennas, an antenna array, or any combination thereof.

[0042]

[0048] Depending on the desired functionality, the wireless communication interface 530 may include separate receivers and transmitters, or any combination of transceivers, transmitters, and / or receivers to communicate with other terrestrial transceivers such as base stations (e.g., ng-eNB and gNB), as well as wireless devices and access points. The UE 120 may communicate with different data networks that may include various 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 (IEEE802.16) network, etc. The CDMA network may implement one or more radio access technologies (RATs) such as CDMA2000, WCDMA, etc. CDMA2000 includes the IS-95, IS-2000, and / or IS-856 standards. The TDMA network may implement GSM, digital advanced mobile phone system (D-AMPS), or some other RAT. The OFDMA network may adopt LTE, LTE-Advanced, 5G NR, etc. 5G NR, LTE, LTE-Advanced, GSM, and WCDMA are described in documents from the Third Generation Partnership Project (3GPP). CDMA2000 is described in documents from a group called "Third Generation Partnership Project 2" (3GPP2). The documents of 3GPP and 3GPP2 are publicly available. The wireless local area network (WLAN) may also be an IEEE802.11x network, and the wireless personal area network (WPAN) may be a Bluetooth network, IEEE802.15x, 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] UE120 may further include one or more sensors 540. The sensors 540 may include, but are not limited to, one or more inertial sensors and / or other sensors (e.g., one or more accelerometers, one or more gyroscopes, one or more cameras, one or more magnetometers, one or more altimeters, one or more microphones, one or more proximity sensors, one or more light sensors, one or more barometers, etc.), and in some cases, some of them may be used to complement and / or facilitate the positioning described herein.

[0044]

[0050] Embodiments of UE120 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. The GNSS receiver 580 can extract the position of UE120 from GNSS SVs of GNSS systems, such as the Global Positioning System (GPS), Galileo, GLONASS, Japan's Quasi-Zenith Satellite System (QZSS), India's Indian Regional Navigation Satellite System (IRNSS), China's Beidou, etc., using conventional techniques. 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 Wide Area Augmentation System (WAAS), European Geostationary Navigation Overlay Service (EGNOS), Multi-functional Satellite Augmentation System (MSAS), and Geo Augmented Navigation system (GAGAN).

[0045]

[0051] UE120 further includes and / or may communicate with a memory 560. The memory 560 can include, without limitation, local storage and / or network-accessible storage, a disk drive, an array of drives, an optical storage device, a random access memory (RAM) that can be programmable, flash updatable, etc., and / or a solid state storage device such as a read only memory (ROM). Such storage devices can be configured to implement any suitable data store, including, without limitation, various file systems, database structures, and the like.

[0046]

[0052] The memory 560 of UE120 can also include computer programs provided by various embodiments, and / or other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, etc. (not shown in FIG. 5), of software elements that can be designed to implement the methods and / or configure the systems provided by other embodiments as described herein. By way of example only, one or more procedures described with respect to the (one or more) methods described above can be implemented as code and / or instructions in the memory 560 that are executable by UE120 (and / or one or more processing units 510 or DSP 520 within UE120). In one aspect, such code and / or instructions can 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 methods.

[0047]

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

[0048]

[0054] Base station 110 is shown comprising hardware elements that may be electrically coupled via bus 605 (or may communicate in other ways as appropriate). The hardware elements may include, without limitation, one or more general-purpose processors, one or more dedicated processors (such as DSP chips, graphics acceleration processors, ASICs, etc.), and / or other processing structures or means, and may include (one or more) processing units 610. 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 communication may be provided in (one or more) processing units 610 and / or wireless communication interface 630 (described below) according to some embodiments. Base station 110 may also include one or more input devices that may include, without limitation, a keyboard, display, mouse, microphone, (one or more) buttons, (one or more) dials, (one or more) switches, etc., and one or more output devices that may include, without limitation, a display, light-emitting diode (LED), speaker, etc.

[0049]

[0055] Base station 110 may include a wireless communication interface 630, which may include, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication device, and / or a chipset (such as a Bluetooth device, an IEEE802.11 device, an IEEE802.15.4 device, a Wi-Fi device, a WiMAX device, cellular communication equipment, 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 a UE, other base stations (e.g., eNB, gNB, and ng-eNB), and / or other network components, computer systems, and / or any other electronic devices described herein. The communication may be performed via one or more wireless communication antennas 632 that send and / or receive wireless signals 634.

[0050]

[0056] 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 enable data to be exchanged with the networks, communication network servers, computer systems, and / or any other electronic devices described herein.

[0051]

[0057] In many embodiments, base station 110 may further include a memory 660. The memory 660 can include, without limitation, local storage and / or network-accessible storage, a disk drive, an array of drives, an optical storage device, a RAM that can be programmable, flash-updatable, etc., and / or a solid-state storage device such as a ROM. Such storage devices can be configured to implement any suitable data store, including, without limitation, various file systems, database structures, and the like.

[0052]

[0058] The memory 660 of base station 110 may also include computer programs provided by various embodiments, and / or other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, that can be designed to implement the methods provided by other embodiments and / or configure the system as described herein. (Software elements not shown in FIG. 6). By way of example only, one or more of the procedures described above with respect to the (one or more) methods described above can be implemented as code and / or instructions in a memory 660 that are executable by base station 110 (and / or one or more processing units 610 or DSP 620 within base station 110). In one aspect, such code and / or instructions can 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 methods described.

[0053]

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

[0054]

[0060] Referring to the accompanying drawings, components that can include memory can include non-transitory machine-readable media. As used herein, the terms "machine-readable media" and "computer-readable media" refer to any storage media involved in providing data that causes a machine to operate in a particular manner. In the embodiments provided above, various machine-readable media can be involved in providing instructions / code to a processing unit and / or one or more other devices for execution. Additionally or alternatively, machine-readable media can be used to store and / or carry such instructions / code. In many implementations, computer-readable media are physical and / or tangible storage media. Such media can 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 media 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 media from which a computer can read instructions and / or code.

[0055]

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

[0056]

[0062] For mainly reasons of general usage, it has been found to be sometimes convenient to refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, digits, etc. However, it should be understood that all of these or similar terms should be associated with appropriate physical quantities and are merely convenient labels. Unless otherwise specified, as is apparent from the above description, throughout this specification, descriptions using terms such as "processing", "calculating", "computing", "determining", "confirming", "identifying", "associating", "measuring", "performing", etc. refer to actions or processes of a specific device, such as a dedicated computer or a similar dedicated electronic computing device. Thus, in the context of this specification, a dedicated computer or a similar dedicated electronic computing device is capable of operating or transforming signals generally represented as electronic, electrical, or magnetic physical quantities within the memory, registers, or other information storage devices, transmission devices, or display devices of the dedicated computer or a similar dedicated electronic computing device.

[0057]

[0063] As used herein, the terms "and" and "or" can include various meanings that are also expected to depend at least in part on the context in which such terms are used. Generally, when "or" is used to associate a list such as A, B, or C, it is intended to mean A, B, and C as used herein in an inclusive sense, as well as A, B, or C as used herein in an exclusive sense. Further, the term "one or more" as used herein can be used to describe any singular feature, structure, or property, or alternatively can be used to describe some combination of features, structures, or properties. However, it should be noted that this is merely an illustrative example and the claimed subject matter is not limited to this example. Further, the term "at least one of" when used to associate a list such as A, B, or C can be interpreted to mean any combination of A, B, and / or C, such as A, AB, AA, AAB, AABBCCC, etc.

[0058]

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

[0059]

[0065] In view of this description, embodiments can include different combinations of features. Implementation examples are described in the following numbered clauses. Clause 1. A method for transmitting a reference signal for positioning in a user equipment (UE), the method comprising: receiving, from a serving base station, a message comprising an instruction for transmitting a sounding reference signal (SRS) on a set of symbols of an orthogonal frequency division multiplexing (OFDM) slot; receiving, from the serving base station, a 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 according to clause 1, wherein the message comprises a radio resource control (RRC) message. Clause 3. The method according to clause 1 or 2, further comprising determining that the SRS should be used for positioning, at least in part based on identifying the positioning designation of the SRS in the RRC message. Clause 4. The method according to any one of clauses 1 to 3, wherein the positioning designation comprises an information element (IE) in the RRC message. Clause 5. The method according to any one of clauses 1 to 4, further comprising determining that the SRS should be used for positioning, at least in part based on determining that the SRS should be transmitted as part of a multi-RTT positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof. Clause 6. The method according to any one of clauses 1 to 4, further comprising determining that the SRS should be used for positioning, at least in part based on determining that the SRS is composed of a downlink (DL) positioning reference signal (PRS). Clause 7. The method according to any one of clauses 1 to 4, further comprising determining that the SRS should be used for positioning, at least in part based on determining that the SRS is related to a non-serving base station. Clause 8. Transmitting the SRS is further based on receiving an indication from the serving base station that it is acceptable to transmit the SRS on flexible symbols, and is the method described in any of Clauses 1 to 7. Clause 9. Transmitting the SRS is further based on receiving an indication from the serving base station that it supports a version of the data communication standard in which it is acceptable to transmit the SRS on flexible symbols, and is the method described in any of Clauses 1 to 8. Clause 10. The indication that it is acceptable to transmit the SRS on flexible symbols is transmitted using the IE in the second message received from the serving base station, and is the method described in Clause 9. Clause 11. The indication that it is acceptable to transmit the SRS on flexible symbols is transmitted from the serving base station using a media access control (MAC) control element (MAC-CE), and is the method described in Clause 9. 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, wherein the one or more processing units are configured to receive, from the serving base station via the wireless transceiver, a message comprising an indication for transmitting 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, a 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 according to Clause 12, wherein the one or more processing units are configured to receive a radio resource control (RRC) message to receive the message. Clause 14. The mobile device according to any of Clauses 12 or 13, wherein one or more processing units are configured to determine that the SRS should be used for positioning, at least in part based on identifying the positioning designation of the SRS in the RRC message. Clause 15. The mobile device according to any of Clauses 12 to 14, wherein one or more processing units are configured to identify an information element (IE) in the RRC message to identify the positioning designation of the SRS in the RRC message. Clause 16. The mobile device according to any of Clauses 12 to 15, wherein one or more processing units are configured to determine that the SRS should be used for positioning, at least in part based on determining that the SRS should be transmitted as part of a multi-RTT positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof. Clause 17. The mobile device according to any of Clauses 12 to 15, wherein one or more processing units are configured to determine that the SRS should be used for positioning, at least in part based on determining that the SRS is composed of a downlink (DL) positioning reference signal (PRS). Clause 18. The mobile device according to any of Clauses 12 to 15, wherein one or more processing units are configured to determine that the SRS should be used for positioning, at least in part based on determining that the SRS is related to a non-serving base station. Clause 19. The mobile device according to any of Clauses 12 to 18, wherein one or more processing units are configured to transmit the SRS, further based on receiving an indication from the serving base station, via the wireless transceiver, that it is acceptable to transmit the SRS on flexible symbols. Clause 20. The mobile device according to any of Clauses 12 to 19, wherein one or more processing units are further configured to transmit SRS based on receiving an indication from a serving base station that the serving base station supports a version of a data communication standard that permits transmitting SRS on flexible symbols via a wireless transceiver. Clause 21. The mobile device according to Clause 20, wherein one or more processing units are configured to receive an indication that it is permissible to transmit SRS on flexible symbols via an IE in a second message received from a serving base station. Clause 22. The mobile device according to Clause 20, wherein one or more processing units are configured to receive an indication that it is permissible to transmit SRS on flexible symbols from a serving base station via a media access control (MAC) control element (MAC-CE). Clause 23. A device comprising means for receiving a message from a serving base station comprising an indication for transmitting 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 a downlink control information (DCI) having a slot format indicator (SFI) designating a subset of the set of symbols as flexible, and means for transmitting SRS for positioning on at least a portion of the subset. Clause 24. The device according to 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 SRS should be used for positioning based at least in part on identifying an SRS positioning designation in the RRC message. Clause 25. The device according to Clause 23 or 24, wherein the means for identifying a positioning designation comprises means for identifying an information element (IE) in the RRC message. Clause 26. The device according to any of Clauses 23 to 25, further comprising means for determining that the SRS should be used for positioning, at least partially based on determining that the SRS should be transmitted as part of a multi-RTT positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof. Clause 27. The device according to any of Clauses 23 to 26, further comprising means for determining that the SRS should be used for positioning, at least partially based on determining that the SRS is constituted by a downlink (DL) positioning reference signal (PRS). Clause 28. The device according to any of Clauses 23 to 26, further comprising means for determining that the SRS should be used for positioning, at least partially based on determining that the SRS is related to 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 receiving, from a serving base station, a message comprising an instruction for transmitting 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 according to Clause 29, wherein the code for receiving a 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, at least partially based on identifying the positioning designation of the SRS in the RRC message. The invention described in the claims of the present application at the time of initial filing is appended below. [C1] A method for transmitting a reference signal for positioning in a user equipment (UE), the method comprising: receiving, from a serving base station, a message comprising an instruction for transmitting 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; transmitting the SRS for positioning on at least a portion of the subset. A method comprising the above. [C2] The method according to C1, wherein the message comprises a radio resource control (RRC) message. [C3] The method according to C2, further comprising determining that the SRS should be used for positioning based at least in part on identifying the positioning designation of the SRS in the RRC message. [C4] The method according to C3, wherein the positioning designation comprises an information element (IE) in the RRC message. [C5] The SRS is a multi-RTT positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof The method according to C1, 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. [C6] The method according to C1, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS is composed of a downlink (DL) positioning reference signal (PRS). [C7] The method according to C1, further comprising determining that the SRS should be used for positioning based at least in part on determining that the SRS is related to a non-serving base station. [C8] The method according to C1, wherein transmitting the SRS is further based on receiving, from the serving base station, an instruction that it is acceptable to transmit the SRS on a flexible symbol. [C9] The method according to C1, wherein transmitting the SRS is further based on receiving an indication from the serving base station that the serving base station supports a version of a data communication standard in which transmitting the SRS on a flexible symbol is acceptable. [C10] The method according to C8, wherein the indication that transmitting the SRS on a flexible symbol is acceptable is conveyed using an IE in a second message received from the serving base station. [C11] The method according to C8, wherein the indication that transmitting the SRS on a flexible symbol is acceptable is conveyed from the serving base station using a media access control (MAC) control element (MAC-CE). [C12] A wireless transceiver, a memory, and one or more processing units communicatively coupled to the wireless transceiver and the memory, wherein the one or more processing units are configured to receive, from a serving base station via the wireless transceiver, a message comprising an indication 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. A mobile device configured to perform the above. [C13] The mobile device according to C12, wherein the one or more processing units are configured to receive a radio resource control (RRC) message to receive the message. [C14] The mobile device according to C13, 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 the positioning designation of the SRS in the RRC message. [C15] The mobile device according to C14, wherein the one or more processing units are configured to identify an information element (IE) in the RRC message in order to identify the positioning designation of the SRS in the RRC message. [C16] The one or more processing units, wherein the SRS is a multi-RTT positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof and is configured to determine that the SRS should be used for positioning, at least in part based on a determination that the SRS should be transmitted as part of. The mobile device according to C12. [C17] The mobile device according to C12, wherein the one or more processing units are configured to determine that the SRS should be used for positioning, at least in part based on a determination that the SRS is composed of a downlink (DL) positioning reference signal (PRS). [C18] The mobile device according to C12, wherein the one or more processing units are configured to determine that the SRS should be used for positioning, at least in part based on a determination that the SRS is related to a non-serving base station. [C19] The mobile device according to C12, wherein the one or more processing units are further configured to transmit the SRS based on receiving an indication from the serving base station that it is permissible to transmit the SRS on flexible symbols via the wireless transceiver. [C20] The mobile device according to C12, wherein the one or more processing units are further configured to transmit the SRS based on receiving an indication from the serving base station that the serving base station supports a version of a data communication standard that permits transmitting the SRS on flexible symbols via the wireless transceiver. [C21] The mobile device according to C19, wherein the one or more processing units are configured to receive the indication that it is permissible to transmit the SRS on flexible symbols via an IE in a second message received from the serving base station. [C22] The mobile device according to C19, wherein the one or more processing units are configured to receive, from the serving base station, via a media access control (MAC) control element (MAC-CE), the indication that it is permissible to transmit the SRS on flexible symbols. [C23] Means for receiving a message from the serving base station, the message comprising an indication for transmitting 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, a downlink control information (DCI) 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. [C24] The device according to C23, wherein the means for receiving the message comprises means for receiving a radio resource control (RRC) message, and further comprises means for determining, at least in part based on identifying the positioning designation of the SRS in the RRC message, that the SRS should be used for positioning. [C25] The device according to C24, wherein the means for identifying the positioning designation comprises means for identifying an information element (IE) in the RRC message. [C26] The SRS is a multi-RTT positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof The device according to C23, further comprising means for determining that the SRS should be used for positioning, at least in part based on determining that the SRS should be transmitted as part of. [C27] The device according to C23, further comprising means for determining that the SRS should be used for positioning, at least in part based on determining that the SRS is composed of a downlink (DL) positioning reference signal (PRS). [C28] The device according to C23, further comprising means for determining that the SRS should be used for positioning, at least in part based on determining that the SRS is related to a non-serving base station. A non-transitory computer-readable medium storing instructions for transmitting a reference signal for positioning, the instructions comprising: Receiving, from a serving base station, a message comprising an instruction for transmitting 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; Transmitting the SRS for positioning on at least a portion of the subset A non-transitory computer-readable medium comprising code for performing the steps. [C30] The non-transitory computer-readable medium according to C29, 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 the positioning designation of the SRS in the RRC message.

Claims

1. A method for transmitting a reference signal for positioning in a user equipment (UE), the method comprising: Receiving, from a serving base station, a message comprising an instruction for transmitting 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; Based on a determination that the SRS is to be used for positioning and an instruction received from the serving base station indicating that it is permissible to transmit the SRS on flexible symbols, transmitting the SRS for positioning on at least a portion of the subset; A method comprising the above.

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

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

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

5. The SRS is a multi-round trip (multi-RTT) positioning session, uplink time difference of arrival (UL-TDOA) positioning, uplink angle of arrival (UL-AoA) positioning, or any combination thereof The method according to claim 1, further comprising determining that the SRS should be used for positioning, at least partially based on a determination that the SRS should be transmitted as part of.

6. The method according to claim 1, further comprising determining that the SRS should be used for positioning, at least partially based on a determination that the SRS is configured in a message having a downlink (DL) positioning reference signal (PRS).

7. The method according to claim 1, further comprising determining that the SRS should be used for positioning, at least partially based on a determination that the SRS is related to a non-serving base station. The method according to claim 1, wherein the indication indicating that it is permissible to transmit the SRS on a flexible symbol is an indication that the serving base station supports a version of a data communication standard in which it is permissible to transmit the SRS on a flexible symbol.

9. The method according to claim 1, wherein the indication indicating that it is permissible to transmit the SRS on a flexible symbol is conveyed using an IE in a second message received from the serving base station.

10. The method according to claim 1, wherein the indication indicating that it is permissible to transmit the SRS on a flexible symbol is conveyed from the serving base station using a media access control (MAC) control element (MAC-CE).

11. A wireless transceiver, a memory, one or more processing units communicatively coupled to the wireless transceiver and the memory, A mobile device comprising: wherein the one or more processing units Receive, from a serving base station via the wireless transceiver, a message comprising an instruction 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; Based on a determination that the SRS is to be used for positioning and an indication received from the serving base station indicating that it is permissible to transmit the SRS on a flexible symbol, transmit the SRS for positioning on at least a portion of the subset via the wireless transceiver; A mobile device configured to perform.

12. The mobile device according to claim 11, wherein the one or more processing units are further configured to execute the method according to any one of claims 2 to 10.

13. A non-transitory computer-readable medium storing instructions for transmitting a reference signal for positioning, the instructions comprising code for performing the method according to any one of claims 1 to 10, the non-transitory computer-readable medium.

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