Methods for configuring reference signals in wireless systems

Abstract

A method performed by WTRU may include receiving PRS configuration information and performing a first set of measurements based on the PRS configuration. The method may further include determining whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria. Under the condition that the decision to trigger is positive, an on-demand PRS request is transmitted. In embodiments, the on-demand PRS criteria may be based on RSRP, TDoA, the number of multipaths, accuracy, and / or latency.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 061,714 filed August 5, 2020; U.S. Provisional Application No. 63 / 091,694 filed October 14, 2020; U.S. Provisional Application No. 63 / 130,037 filed December 23, 2020; U.S. Provisional Application No. 63 / 167,781 filed March 30, 2021; and U.S. Provisional Application No. 63 / 185,710 filed May 7, 2021, the contents of which are incorporated herein by reference.

[0003] A method performed by a wireless transmit / receive unit (WTRU) may include receiving a positioning reference signal (PRS) configuration and performing a first set of measurements based on the PRS configuration. The method may further include determining whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria. Under the condition that the decision to trigger is positive, the on-demand PRS request is transmitted. In embodiments, the on-demand PRS criteria may be based on reference signal receive power (RSRP), time difference of arrival (TDoA), number of multipaths, accuracy, and / or latency. Brief explanation of the drawing

[0004] A more detailed understanding can be obtained from the following description, given as an example together with the attached drawings, where similar reference numbers in the drawings indicate similar elements. FIG. 1a is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented. FIG. 1b is a system diagram illustrating an exemplary wireless transceiver unit (WTRU) that can be used within the communication system illustrated in FIG. 1a according to an embodiment. FIG. 1c is a system diagram illustrating an exemplary radio access network (RAN) and an exemplary core network (CN) that can be used within the communication system illustrated in FIG. 1a according to an embodiment. FIG. 1d is a system diagram illustrating additional exemplary RAN and additional exemplary CN that can be used within the communication system illustrated in FIG. 1a according to an embodiment. FIG. 2 is a signal flowchart illustrating a procedure for enabling dynamic and on-demand positioning reference signals (PRS). FIG. 3 is a signal flowchart illustrating a procedure for enabling on-demand and dynamic sounding reference signals (SRS). Figure 4 is an example of WTRU performing bundling of multiple measurement opportunities. Figure 5 is an example of a WTRU having two configured measurement gaps (MG) that determine whether to stop monitoring the PDCCH. Figure 6 is an example of a WTRU performing non-periodic reception of a periodic PRS. Figure 7 is an example of a WTRU performing semi-continuous reception of periodic PRS. Figure 8 is an example of a WTRU performing measurements on periodic PRS at measurement opportunities of different frequencies than when the PRS is transmitted. Figure 9 is a flowchart of the procedure for transmitting an on-demand PRS reconfiguration request. Specific details for implementing the invention

[0005] FIG. 1a is a drawing illustrating an exemplary communication system (100) in which one or more disclosed embodiments may be implemented. The communication system (100) may be a multiple access system that provides content such as voice, data, video, messaging, broadcasting, etc. to multiple wireless users. The communication system (100) may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication systems (100) may use one or more channel access methods such as CDMA (code division multiple access), TDMA (time division multiple access), FDMA (frequency division multiple access), OFDMA (orthogonal FDMA), SC-FDMA (single-carrier FDMA), ZT-UW-DFT-S-OFDM (zero-tail unique-word discrete Fourier transform Spread OFDM), UW-OFDM (unique word OFDM), resource block filtered OFDM, FBMC (filter bank multicarrier), etc.

[0006] As illustrated in FIG. 1a, the communication system (100) may include radio transceiver units (WTRUs) (102a, 102b, 102c, 102d), a radio access network (RAN) (104), a core network (CN) (106), a public switched telephone network (PSTN) (108), the Internet (110), and other networks (112), but it will be recognized that the disclosed embodiments consider any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs (102a, 102b, 102c, 102d) may be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRUs (102a, 102b, 102c, 102d)—any of which may be referred to as a “station”—may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain situations), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs (102a, 102b, 102c, and 102d) may be interchangeably referred to as WTRU.

[0007] Communication systems (100) may also include a base station (114a) and / or a base station (114b). Each of the base stations (114a, 114b) may be any type of device configured to wirelessly interface with at least one of the WTRUs (102a, 102b, 102c, 102d) to facilitate access to one or more communication networks, such as, for example, CN (106), the Internet (110), and / or other networks (112). For example, the base stations (114a, 114b) may be a next-generation NodeB such as a BTS (base transceiver station), NodeB, eNode B (eNB), Home Node B, Home eNode B, eNode B, eNode B, gNode B (gNB), a site controller, an access point (AP), a wireless router, etc. Base stations (114a, 114b) are each depicted as a single element, but it will be understood that base stations (114a, 114b) may include any number of interconnected base stations and / or network elements.

[0008] A base station (114a) may be part of a RAN (104), and the RAN (104) may also include other base station and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station (114a) and / or base station (114b) may be configured to transmit and / or receive radio signals on one or more carrier frequencies that may be referred to as cells (not shown). These frequencies may be within the licensed spectrum and the unlicensed spectrum, or a combination of the licensed spectrum and the unlicensed spectrum. A cell may provide coverage for radio services for a specific geographical area that may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, a cell associated with a base station (114a) may be divided into three sectors. Accordingly, in one embodiment, the base station (114a) may include three transceivers, that is, one for each sector of the cell. In an embodiment, the base station (114a) may employ MIMO (multiple-input multiple-output) technology and may use multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0009] Base stations (114a, 114b) can communicate with one or more of WTRUs (102a, 102b, 102c, 102d) through an air interface (116) which may be any suitable radio communication link (e.g., RF (radio frequency), microwave, centimeter wave, micrometer wave, IR (infrared), UV (ultraviolet), visible light, etc.). The air interface (116) may be established using any suitable radio access technology (RAT).

[0010] More specifically, as described above, the communication system (100) may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations (114a) and WTRUs (102a, 102b, 102c) within the RAN (104) may implement wireless technology such as Universal Mobile Communications System (UMTS) terrestrial radio access (UTRA) that can establish an air interface (116) using broadband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or advanced HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (uplink, UL) (HSUPA).

[0011] In an embodiment, the base station (114a) and WTRUs (102a, 102b, 102c) can implement wireless technology such as E-UTRA (Evolved UMTS Terrestrial Radio Access) which can establish an air interface (116) using, for example, LTE (Long Term Evolution) and / or LTE-A (LTE-Advanced) and / or LTE-A Pro (LTE-Advanced Pro).

[0012] In an embodiment, the base station (114a) and WTRUs (102a, 102b, 102c) can implement wireless technology such as NR wireless access that can establish an air interface (116) using NR.

[0013] In an embodiment, the base station (114a) and WTRUs (102a, 102b, 102c) may implement a number of wireless access technologies. For example, the base station (114a) and WTRUs (102a, 102b, 102c) may implement LTE wireless access and NR wireless access together, for example, using dual connectivity (DC) principles. Accordingly, the air interface used by the WTRUs (102a, 102b, 102c) may be characterized by a number of types of wireless access technologies and / or transmitters transmitted to / from a number of types of base stations (e.g., eNB and gNB).

[0014] In another embodiment, the base station (114a) and WTRUs (102a, 102b, 102c) can implement wireless technologies such as IEEE 802.11 (i.e., WiFi (Wireless Fidelity)), IEEE 802.16 (i.e., WiMAX (Worldwide Interoperability for Microwave Access)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, IS-2000 (Interim Standard 2000), IS-95 (Interim Standard 95), IS-856 (Interim Standard 856), GSM (Global System for Mobile communications), EDGE (Enhanced Data rates for GSM Evolution), GERAN (GSM EDGE), etc.

[0015] The base station (114b) of FIG. 1a may be, for example, a wireless router, a home Node B, a home eNode B, or an access point, and any suitable RAT may be used to facilitate wireless connectivity in a localized area such as, for example, a workplace, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station (114b) and WTRUs (102c, 102d) may establish a wireless local area network (WLAN) by implementing a wireless technology such as IEEE 802.11. In one embodiment, the base station (114b) and WTRUs (102c, 102d) may implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In another embodiment, the base station (114b) and WTRUs (102c, 102d) may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. As illustrated in FIG. 1a, the base station (114b) may have direct access to the Internet (110). Thus, the base station (114b) may not be required to access the Internet (110) via the CN (106).

[0016] The RAN (104) may communicate with a CN (106), which may be any type of network configured to provide voice, data, applications, and / or VoIP (voice over internet protocol) services to one or more of the WTRUs (102a, 102b, 102c, 102d). The data may have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN (106) may provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication, for example. Although not illustrated in FIG. 1a, it will be understood that the RAN (104) and / or CN (106) may communicate directly or indirectly with other RANs employing the same RAT as the RAN (104) or a different RAT. In addition to access to the RAN (104), which may, for example, use NR wireless technology, the CN (106) may also communicate with another RAN (not illustrated) using GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi wireless technology.

[0017] CN (106) may also serve as a gateway for WTRUs (102a, 102b, 102c, 102d) to access the PSTN (108), the Internet (110), and / or other networks (112). The PSTN (108) may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet (110) may include a global system of interconnected computer networks and devices using common communication protocols such as TCP, User Datagram Protocol (UDP), and / or IP in the transmission control protocol / internet protocol (TCP / IP) suite. The networks (112) may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, networks (112) may include another CN connected to one or more RANs that can use the same RAT or a different RAT as the RAN (104).

[0018] Some or all of the WTRUs (102a, 102b, 102c, 102d) within the communication system (100) may include multi-mode capabilities (e.g., the WTRUs (102a, 102b, 102c, 102d) may include multiple transceivers to communicate with different wireless networks via different wireless links). For example, the WTRU (102c) illustrated in FIG. 1a may be configured to communicate with a base station (114a) capable of employing cellular-based wireless technology and a base station (114b) capable of employing IEEE 802 wireless technology.

[0019] FIG. 1b is a system diagram illustrating an exemplary WTRU (102). As illustrated in FIG. 1b, the WTRU (102) may include, in particular, a processor (118), a transceiver (120), a transceiver element (122), a speaker / microphone (124), a keypad (126), a display / touchpad (128), non-removable memory (130), removable memory (132), a power supply (134), a GPS (global positioning system) chipset (136), and / or other peripherals (138). It will be understood that the WTRU (102) may include any sub-combination of the aforementioned elements while remaining consistent with the embodiment.

[0020] The processor (118) may be a general-purpose processor, a special-purpose processor, a traditional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), any other type of IC, a state machine, etc. The processor (118) may perform signal coding, data processing, power control, input / output processing, and / or any other function that enables the WTRU (102) to operate in a wireless environment. The processor (118) may be coupled to a transceiver (120) that may be coupled to a transceiver element (122). Although FIG. 1b illustrates the processor (118) and the transceiver (120) as separate components, it will be known that the processor (118) and the transceiver (120) may be integrated together within an electronic package or chip.

[0021] The transceiver element (122) may be configured to transmit a signal to a base station (e.g., base station (114a)) or receive a signal therefrom through the air interface (116). For example, in one embodiment, the transceiver element (122) may be an antenna configured to transmit and / or receive an RF signal. In an embodiment, the transceiver element (122) may be an emitter / detector configured to transmit and / or receive an IR, UV, or visible light signal, for example. In another embodiment, the transceiver element (122) may be configured to transmit and / or receive both an RF signal and an optical signal. It will be known that the transceiver element (122) may be configured to transmit and / or receive any combination of radio signals.

[0022] Although the transmitting and receiving element (122) is illustrated as a single element in FIG. 1b, the WTRU (102) may include any number of transmitting and receiving elements (122). More specifically, the WTRU (102) may employ MIMO technology. Accordingly, in one embodiment, the WTRU (102) may include two or more transmitting and receiving elements (122) (e.g., multiple antennas) for transmitting and receiving wireless signals through the air interface (116).

[0023] The transceiver (120) may be configured to modulate a signal to be transmitted by the transceiver element (122) and to demodulate a signal received by the transceiver element (122). As previously described, the WTRU (102) may have multimode capabilities. Accordingly, the transceiver (120) may include multiple transceivers to enable the WTRU (102) to communicate through multiple RATs, such as NR and IEEE 802.11, for example.

[0024] The processor (118) of the WTRU (102) may be coupled to a speaker / microphone (124), a keypad (126), and / or a display / touch pad (128) (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input data from them. The processor (118) may also output user data to the speaker / microphone (124), the keypad (126), and / or the display / touch pad (128). Additionally, the processor (118) may access information from any type of suitable memory, such as non-removable memory (130) and / or removable memory (132), and store data therein. Non-removable memory (130) may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory (132) may include a subscriber identification module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor (118) may access information from memory that is not physically located on the WTRU (102), such as a server or home computer (not shown), and store data therein.

[0025] The processor (118) can receive power from the power source (134) and can be configured to distribute and / or control the power to other components within the WTRU (102). The power source (134) may be any suitable device for supplying power to the WTRU (102). For example, the power source (134) may include one or more batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0026] The processor (118) may also be coupled to a GPS chipset (136) which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU (102). In addition to or instead of information from the GPS chipset (136), the WTRU (102) may receive location information from a base station (e.g., base stations (114a, 114b)) via the air interface (116) and / or determine its location based on the timing of signals received from two or more nearby base stations. The WTRU (102) will know that it may obtain location information by any suitable location determination method while still being consistent with the embodiment.

[0027] The processor (118) may be further coupled to other peripherals (138) which may include one or more software and / or hardware modules that provide additional features, functions and / or wired or wireless connectivity. For example, peripherals (138) may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. Peripherals (138) may include one or more sensors. The sensors may include a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; It may be one or more of an altimeter, optical sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, humidity sensor, etc.

[0028] The WTRU (102) may include a full-duplex radio in which the transmission and reception of some or all of the signals (associated with specific subframes for both the UL (e.g., for transmission) and the DL (e.g., for reception)) may be concomitant and / or simultaneous. The full-duplex radio may include an interference management unit that reduces and / or substantially eliminates self-interference through hardware (e.g., a choke) or through signal processing through a processor (e.g., a separate processor (not shown) or processor (118)). In an embodiment, the WTRU (102) may include a half-duplex radio for the transmission and reception of some or all of the signals (associated with specific subframes for the UL (e.g., for transmission) or the DL (e.g., for reception).

[0029] FIG. 1c is a system diagram illustrating a RAN (104) and a CN (106) according to an embodiment. As previously described, the RAN (104) may employ E-UTRA radio technology to communicate with WTRUs (102a, 102b, 102c) through an air interface (116). The RAN (104) may also communicate with the CN (106).

[0030] The RAN (104) may include eNode-Bs (160a, 160b, 160c), but it will be recognized that the RAN (104) may include any number of eNode-Bs while remaining consistent with the embodiment. Each of the eNode-Bs (160a, 160b, 160c) may include one or more transceivers to communicate with WTRUs (102a, 102b, 102c) via the air interface (116). In one embodiment, the eNode-Bs (160a, 160b, 160c) may implement MIMO technology. Thus, the eNode-B (160a) may use multiple antennas to transmit radio signals to the WTRU (102a), for example, and / or receive radio signals from it.

[0031] Each of the eNode-Bs (160a, 160b, 160c) may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG. 1c, the eNodeBs (160a, 160b, 160c) may communicate with each other via an X2 interface.

[0032] The CN (106) illustrated in FIG. 1c may include a Mobility Management Entity (MME) (162), a Serving Gateway (SGW) (164), and a Packet Data Network (PDN) Gateway (PGW) (166). Although the aforementioned elements are depicted as part of the CN (106), it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0033] The MME (162) can be connected to each of the eNode-Bs (162a, 162b, 162c) within the RAN (104) via the S1 interface and can act as a control node. For example, the MME (162) may be responsible for authenticating users of the WTRUs (102a, 102b, 102c), enabling / disabling bearers, and selecting a specific serving gateway during the initial attach of the WTRUs (102a, 102b, 102c). The MME (162) may provide control plane functions for switching between the RAN (104) and other RANs (not shown) using other wireless technologies such as GSM and / or WCDMA.

[0034] The SGW (164) can be connected to each of the eNode Bs (160a, 160b, 160c) within the RAN (104) via the S1 interface. The SGW (164) can generally route and forward user data packets to and from the WTRUs (102a, 102b, 102c). The SGW (164) can perform other functions such as anchoring user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs (102a, 102b, 102c), and managing and storing the context of the WTRUs (102a, 102b, 102c).

[0035] The SGW (164) can be connected to a PGW (166) that can provide access to packet-switched networks, such as the Internet (110), to the WTRUs (102a, 102b, 102c) to facilitate communication between the WTRUs (102a, 102b, 102c) and IP-enabled devices.

[0036] CN (106) can facilitate communication with other networks. For example, CN (106) can provide WTRUs (102a, 102b, 102c) with access to circuit-switched networks, such as PSTN (108), to facilitate communication between WTRUs (102a, 102b, 102c) and traditional ground communication devices. For example, CN (106) may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between CN (106) and PSTN (108). Additionally, CN (106) can provide WTRUs (102a, 102b, 102c) with access to other networks (112), which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0037] Although the WTRU is described as a wireless terminal in FIGS. 1a through 1d, it is considered that in certain representative embodiments, such a terminal may use wired communication interfaces with a communication network (e.g., temporarily or permanently).

[0038] In a typical embodiment, another network (112) may be a WLAN.

[0039] A WLAN in Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more Stations (STAs) associated with the AP. The AP may have access or an interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic to and / or from the BSS. Traffic originating from outside the BSS to the STAs may arrive through the AP and be forwarded to the STAs. Traffic originating from the STAs to destinations outside the BSS may be transmitted to the AP to be forwarded to their respective destinations. Traffic between STAs within the BSS may be transmitted through the AP; for example, a source STA may send traffic to the AP, and the AP may forward the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be transmitted between a source STA and a destination STA (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z TDLS (tunneled DLS). A WLAN using Independent BSS (IBSS) mode may not have an AP, and STAs within or using IBSS (e.g., all STAs) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

[0040] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit a beacon on a fixed channel, such as the main channel. The main channel can be a fixed width (e.g., a bandwidth of 20 MHz) or a dynamically configured width. The main channel can be the operating channel of the BSS and can be used by STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example, in 802.11 systems. In the case of CSMA / CA, STAs including the AP (e.g., all STAs) can sense the main channel. If the main channel is sensed / detected and / or determined to be in use by a specific STA, that specific STA may be backed off. Only one STA (e.g., only one station) may transmit at any given time in a given BSS.

[0041] High Throughput (HT) STAs can use a 40 MHz wide channel for communication, for example, by combining an adjacent or non-adjacent 20 MHz channel and a main 20 MHz channel to form a 40 MHz wide channel.

[0042] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining adjacent 20 MHz channels. A 160 MHz channel can be formed by combining eight adjacent 20 MHz channels, or by combining two non-adjacent 80 MHz channels, which may be referred to as an 80+80 configuration. In the case of an 80+80 configuration, data can be passed through a segment parser capable of splitting the data into two streams after channel encoding. Inverse Fast Fourier Transform (IFFT) processing and time domain processing can be performed individually for each stream. The streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the aforementioned operation for the 80+80 configuration can be reversed, and the combined data can be transmitted to the Medium Access Control (MAC).

[0043] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using the non-TVWS spectrum. According to a representative embodiment, 802.11ah can support Meter Type Control / Machine-Type Communications (MTC), such as MTC devices within a macro coverage area. MTC devices may have limited capabilities, such as support for specific and / or limited bandwidths (e.g., support only for them). MTC devices may include batteries having a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0044] WLAN systems capable of supporting multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as the main channel. The main channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs within the BSS. The bandwidth of the main channel may be set and / or limited by the STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In the example of 802.11ah, the main channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support the 1 MHz mode (e.g., only that mode), even if the AP and other STAs within the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the state of the main channel. If the main channel is in use, for example, due to transmission to an AP of a STA (which supports only 1 MHz operation mode), all available frequency bands may be considered in use even if most of the available frequency bands remain idle.

[0045] In the United States, the available frequency bands available for use by 802.11ah are 902 MHz to 928 MHz. In Korea, the available frequency bands are 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0046] FIG. 1d is a system diagram illustrating a RAN (104) and a CN (106) according to an embodiment. As mentioned above, the RAN (104) may employ NR radio technology to communicate with WTRUs (102a, 102b, 102c) through an air interface (116). The RAN (104) may also communicate with the CN (106).

[0047] It will be understood that the RAN (104) may include gNBs (180a, 180b, 180c), but the RAN (104) may include any number of gNBs while remaining consistent with the embodiment. Each of the gNBs (180a, 180b, 180c) may include one or more transceivers for communicating with the WTRUs (102a, 102b, 102c) via the air interface (116). In one embodiment, the gNBs (180a, 180b, 180c) may implement MIMO technology. For example, the gNBs (180a, 108b) may use beamforming to transmit signals to the gNBs (180a, 180b, 180c) and / or receive signals from them. Accordingly, the gNB (180a) may use multiple antennas to transmit radio signals to, for example, the WTRU (102a) and / or receive radio signals from it. In an embodiment, the gNBs (180a, 180b, 180c) may implement carrier aggregation technology. For example, the gNB (180a) may transmit multiple component carriers to the WTRU (102a) (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs (180a, 180b, 180c) may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU (102a) may receive coordinated transmissions from the gNB (180a) and the gNB (180b) (and / or the gNB (180c)).

[0048] WTRUs (102a, 102b, 102c) can communicate with gNBs (180a, 180b, 180c) using transmits associated with scalable numerology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmits, different cells, and / or different parts of the radio transmission spectrum. WTRUs (102a, 102b, 102c) can communicate with gNBs (180a, 180b, 180c) using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., including varying numbers of OFDM symbols and / or lasting, varying absolute time lengths).

[0049] gNBs (180a, 180b, 180c) may be configured to communicate with WTRUs (102a, 102b, 102c) in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, WTRUs (102a, 102b, 102c) may communicate with gNBs (180a, 180b, 180c) without also accessing other RANs (e.g., eNodeBs (160a, 160b, 160c)). In a standalone configuration, WTRUs (102a, 102b, 102c) may use one or more of the gNBs (180a, 180b, 180c) as mobility anchor points. In a standalone configuration, WTRUs (102a, 102b, 102c) can communicate with gNBs (180a, 180b, 180c) using signals within the unlicensed band. In a non-standalone configuration, WTRUs (102a, 102b, 102c) can also communicate with gNBs (180a, 180b, 180c) while communicating with another RAN, such as eNode-Bs (160a, 160b, 160c). For example, WTRUs (102a, 102b, 102c) can implement DC principles to communicate substantially simultaneously with one or more gNBs (180a, 180b, 180c) and one or more eNode-Bs (160a, 160b, 160c). In a non-standalone configuration, eNode-Bs (160a, 160b, 160c) can serve as mobility anchors for WTRUs (102a, 102b, 102c), and gNBs (180a, 180b, 180c) can provide additional coverage and / or throughput to service WTRUs (102a, 102b, 102c).

[0050] Each of the gNBs (180a, 180b, 180c) may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, scheduling of users in UL and / or DL, support for network slicing, interoperability between DC, NR and E-UTRA, routing of user plane data to User Plane Functions (UPF) (184a, 184b), routing of control plane information to Access and Mobility Management Functions (AMF) (182a, 182b), etc. As shown in FIG. 1d, the gNBs (180a, 180b, 180c) may communicate with each other via an Xn interface.

[0051] The CN (106) illustrated in FIG. 1d may include at least one AMF (182a, 182b), at least one UPF (184a, 184b), at least one Session Management Function (SMF) (183a, 183b), and possibly a Data Network (DN) (185a, 185b). Although the aforementioned elements are depicted as part of the CN (106), it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0052] The AMF (182a, 182b) can be connected to one or more of the gNBs (180a, 180b, 180c) within the RAN (104) via the N2 interface and can act as a control node. For example, the AMF (182a, 182b) can be responsible for the authentication of users of the WTRUs (102a, 102b, 102c), support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selection of a specific SMF (183a, 183b), management of the registration area, termination of non-access stratum (NAS) signaling, and mobility management. Network slicing may be used by AMF (182a, 182b) to customize CN support for WTRUs (102a, 102b, 102c) based on the types of services used by WTRUs (102a, 102b, 102c). For example, different network slices may be established for different use cases, such as services relying on URLLC (ultra-reliable low latency) access, services relying on eMBB (enhanced massive mobile broadband) access, services for MTC access, etc. AMF (182a, 182b) may provide control plane functions for switching between RAN (104) and other RANs (not shown) using other radio technologies, such as, for example, LTE, LTE-A, LTE-A Pro and / or non-3GPP access technologies such as WiFi.

[0053] SMF (183a, 183b) can be connected to AMF (182a, 182b) within CN (106) via the N11 interface. SMF (183a, 183b) can also be connected to UPF (184a, 184b) within CN (106) via the N4 interface. SMF (183a, 183b) can select and control UPF (184a, 184b) and configure the routing of traffic through UPF (184a, 184b). SMF (183a, 183b) can perform other functions such as managing and assigning WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing DL data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0054] UPF (184a, 184b) may be connected to one or more of gNBs (180a, 180b, 180c) within the RAN (104) via an N3 interface that can provide access to packet-switched networks, such as the Internet (110), to WTRUs (102a, 102b, 102c) to facilitate communication between WTRUs (102a, 102b, 102c) and IP-enabled devices. UPF (184, 184b) may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-hom PDU sessions, handling user plane QoS, buffering DL packets, and providing mobility anchoring.

[0055] CN (106) can facilitate communication with other networks. For example, CN (106) may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between CN (106) and PSTN (108). Additionally, CN (106) may provide WTRUs (102a, 102b, 102c) with access to other networks (112), which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs (102a, 102b, 102c) can be connected to local DNs (185a, 185b) through UPF (184a, 184b) via an N3 interface to UPF (184a, 184b) and an N6 interface between UPF (184a, 184b) and DNs (185a, 185b).

[0056] In reference to FIGS. 1a through 1d and the corresponding description of FIGS. 1a through 1d, one or more or all of the functions described herein in connection with one or more of WTRU (102a through 102d), base station (114a, 114b), eNode-B (160a through 160c), MME (162), SGW (164), PGW (166), gNB (180a through 180c), AMF (182a, 182b), UPF (184a, 184b), SMF (183a, 183b), DN (185a, 185b) and / or any other device(s) described herein may be performed by one or more emulation devices (not shown). Emulation devices may be one or more devices configured to emulate one or all of the functions described herein. For example, emulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0057] Emulation devices may be designed to implement one or more tests of other devices in laboratory environments and / or operator network environments. For example, one or more emulation devices may perform one or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within a communication network. One or more emulation devices may perform one or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. An emulation device may be directly coupled to another device for testing and / or to perform testing using over-the-air (OTA) wireless communication.

[0058] One or more emulation devices may perform one or more functions including all functions without being implemented or deployed as part of a wired and / or wireless communication network. For example, emulation devices may be used in test scenarios in a test laboratory and / or in a wired and / or wireless communication network that is not deployed (e.g., test) to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication through an RF circuit (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0059] The semi-static configuration of the Positioning Reference Signal (PRS) and the Sounding Reference Signal (SRS) for Positioning is specified. The PRS and SRS are configured by the LTE Positioning Protocol (LPP) and RRC protocols, respectively. Depending on the methods used for positioning, the network configures the PRS and / or SRS for the positioning of the WTRU.

[0060] Positioning may require both low latency and high accuracy. Current semi-statically configured positioning parameters do not enable the system to achieve these goals. Therefore, methods may be needed to allow the WTRU to request a reconfiguration.

[0061] In some embodiments, the WTRU may be configured to dynamically transmit a reconfiguration / on-demand request for a reference signal (RS) configuration, such as a PRS and / or SRS (SRSp) configuration for positioning, which enables the WTRU to satisfy positioning-related QoS requirements, which may include high accuracy and low latency requirements among other potential ones. The embodiments described herein may be used to request RSs of other types, as well as RSs that may or may not be dedicated to positioning, for example.

[0062] To support on-demand PRS / SRS, the Location Management Function (LMF) may initially provide and / or configure one or more allowed PRS / SRS configurations to the serving gNB associated with the WTRU and other gNBs within the RAN, for example, using NR Positioning Protocol A (NRPPa). The WTRU may also be pre-configured with one or more PRS / SRS configurations that can be supported by the network for DL / UL positioning, wherein the PRS / SRS configurations configured in the WTRU may correspond to the PRS / SRS configurations provided to the serving gNBs. Different PRS / SRS pre-configurations supported by the network may be provided to the WTRU by either an LMF using LPP / NAS signaling or a serving gNB using RRC signaling.

[0063] For DL ​​positioning, the WTRU may subsequently perform one or more PRS measurements on the PRS configuration indicated by the WTRU in an on-demand PRS request. Likewise, for UL positioning, the network may perform measurements on the SRS transmitted by the WTRU and the SRS configuration indicated by the WTRU in an on-demand SRS request / selection indication.

[0064] Some of the advantages of the methods described herein include improved accuracy for positioning, reduced latency for positioning at both the physical and network layers, and reduced overhead for configuration for positioning.

[0065] It should be noted that in this description, "SRS for positioning" refers to the SRS signal / transmission used for positioning. Resources for the SRS for positioning may be defined by the RRC (e.g., signaled). In Rel. 16, the set of SRS resources configured for positioning and the SRS resources are specified. However, in this detailed description, “SRS for positioning” or “SRS” may include at least one of the following: an SRS configured under SRS-PosResourceSet-r16 and SRS-PosResource-r16; an SRS configured under SRS-ResourceSet and SRS-Resource; an SRS not configured under SRS-PosResourceSet-r16 and SRS-PosResource-r16; an SRS not configured under SRS-ResourceSet and SRS-Resource; an SRS not associated with SRS-PosResourceSet-r16, SRS-PosResource-r16, SRS-ResourceSet or SRS-Resource; an uplink reference signal associated for positioning; a DMRS for the uplink; and / or a PTRS for the uplink. The terms PRS and SRS as used in this description are not intended to be limited to RSs used for positioning. The methods described in this specification may be applied to or used with any DL or UL reference signals.

[0066] FIG. 2 illustrates a procedure (200) for enabling dynamic and on-demand PRS. A WTRU (202) may receive an LPP from a gNB (204) having one or more allowed PRS configurations and upper layer (HL) trigger conditions (208). The gNB (204) may receive one or more PRS pre-configurations via NRPPa (210). The gNB (204) may provide access layer triggers and / or conditions to the WTRU (202) via RRC (212). A trigger (214) for determining a PRS may be initiated by the WTRU (202). The WTRU (202) may transmit an on-demand PRS indication to the network via the gNB (204) to request a PRS configuration based on the configured triggering conditions (216). In one embodiment, the WTRU may transmit a reconfiguration / on-demand indication to a serving gNB to request an RS configuration, such as a PRS, to perform an RS measurement based on the detection of one or more triggering conditions configured by the WTRU. The embodiments described herein may also be used to request other types of RS. To determine the PRS configuration to be indicated in the on-demand PRS re-request, the WTRU may be configured with triggering conditions / criteria and mapping rules for mapping between the triggering conditions and the PRS configurations. For example, the mapping rules may indicate that for each of the different PRS configurations that may be identified by a configuration identifier (ID), there may be one or more associated triggering conditions that can be monitored and detected by the WTRU to determine the PRS configuration.

[0067] The WTRU may receive different PRS configurations, associated triggering conditions, and mapping rules from the LMF (206) in an auxiliary information message that may be returned from an upper-layer NAS message. Alternatively, the WTRU may also receive PRS configurations and mapping rules from the serving gNB (204) in a dedicated RRC message or a broadcast RRC message (SIB) (218). The different triggering conditions and mapping rules received by the WTRU may include one or more combinations of events / parameters associated with the upper layer and / or access layer (AS) layer. In one example, the triggering conditions and mapping rules associated with the upper layer may be received from the LMF, while the triggering conditions and mapping rules associated with the AS layer may be received from the serving gNB. In another example, both the upper layer and AS layer related triggering conditions and mapping rules may be received from the serving gNB.

[0068] Different triggering conditions that may be configured in WTRU are described herein. For example, a mapping rule associated with an upper layer may indicate a first PRS configuration when the WTRU speed is within a first speed range and / or a second PRS configuration when the WTRU speed is within a second speed range. Likewise, a mapping rule associated with an AS layer may indicate determining a first PRS configuration when the buffer state in one or more LCHs is below a threshold and / or determining a second PRS configuration when the buffer state in the LCHs is greater than the threshold.

[0069] When dynamically determining the PRS configuration, the WTRU may send an on-demand indication to the network requesting the transmission of the PRS. The on-demand indication may be sent by the WTRU in any one of uplink control information (UCI) (e.g., SR), UL MAC CE, or RRC messages. The content of the on-demand indication for the PRS may include one or more of a request for the PRS, a selected PRS configuration, a determined PRS configuration, and / or WTRU status information.

[0070] For example, using a request for PRS, an indication that can trigger the initialization of PRS transmission using a PRS configuration that can be pre-configured on the network can be transmitted by the WTRU.

[0071] For example, using a selected PRS configuration, WTRU can represent the identifier of the selected PRS configuration, which can be selected from a set of PRS preconfigurations based on configured mapping rules.

[0072] For example, using a determined PRS configuration, WTRU can represent the configuration of the determined PRS configuration, which can be determined based on a configured formula / expression that can map between triggering conditions and the PRS configuration.

[0073] For example, using WTRU status information, the WTRU can indicate status information (e.g., WTRU speed, direction) related to events / conditions applicable to the WTRU, which can be identified based on configured triggering conditions. In this case, the selection of PRS configuration can be performed by the network based on the indicated WTRU status information.

[0074] When the WTRU transmits an on-demand indication for the PRS, it may initiate monitoring of one or more measurement(s) and the reception of the PRS. To trigger the PRS measurement, the WTRU may transition immediately after transmitting the on-demand indication or transition when it receives a confirmation from the network (e.g., in a DCI, DL MAC CE, or RRC message) acknowledging the transmission of the requested PRS. Subsequently, the WTRU may perform the PRS measurement (220) and transmit the generated measurement report to the LMF (222). In WTRU auxiliary positioning, the measurement report may include measurements taken for a determined PRS configuration. In WTRU-based positioning, the measurement report may include location information of the WTRU (e.g., coordinates) determined based on the PRS measurements and the configured auxiliary information.

[0075] Some of the advantages obtained from the above methods may include reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0076] In some embodiments, the LMF initiates an on-demand request for a PRS. The WTRU receives a new / updated PRS configuration as a result of the LMF-initiated on-demand request, which may be generated based on an indication including a request or measurement report transmitted by the WTRU. In the LMF-initiated on-demand request, the updated PRS configuration received by the WTRU may augment an existing PRS configuration (e.g., including additional resources, resource sets, and transmission reception points (TRPs)) and / or overwrite an existing PRS configuration (e.g., changing or removing resources, resource sets, and TRPs). In other examples, the WTRU may receive a PRS transmission due to an LMF-initiated on-demand request that may be correlated with an indication (i.e., a request or measurement report) transmitted by the WTRU. The LMF-initiated on-demand request may include a request ID and be identified by it. Additionally, on-demand requests may also be associated with a priority value, which may be used by a receiving WTRU or RAN node to prioritize specific actions indicated in the on-demand requests. For example, if the priority indicated in one or more received on-demand requests for a first PRS configuration is higher than that of a second PRS configuration, the WTRU may update the first PRS configuration before updating the second PRS configuration.

[0077] In another embodiment, the WTRU may implicitly trigger an LMF-initiated on-demand request based on a measurement report provided by the WTRU to perform a reconfiguration in the network (e.g., adding or removing beams and / or TRPs). In this case, the network reconfiguration may or may not be associated with a PRS configuration applied by the WTRU. For example, an LMF-initiated on-demand request may be sent to a TRP / gNB to turn off one or more beams that are not measurable by the WTRU or are not useful for improving WTRU positioning accuracy. Similarly, the TRP / gNB may be triggered by an on-demand request to turn on certain beams when a measurement report sent by the WTRU explicitly or implicitly indicates the potential to improve WTRU positioning accuracy. In this case, the WTRU may include one or more beam IDs in the measurement report sent to the LMF, which may or may not be part of the associated PRS configuration applied by the WTRU.

[0078] In some embodiments, an LMF-initiated request for demand may also be referred to as a network-initiated request for demand. An LMF-initiated request for demand may also be related to a RAN-initiated request for demand, which may be triggered by a RAN node (e.g., gNB or TRP) based on indications received from the LMF.

[0079] The WTRU may receive an LMF-initiated request for an order containing one or more new PRS configurations directly from the LMF via NAS signaling (e.g., in an LPP auxiliary transport procedure, a location request / transport procedure) or in a SIB broadcast message. Alternatively, the LMF-initiated request for an order may be received indirectly through a serving gNB within the RAN via RRC signaling, MAC CE, or DCI. In some examples, a combination of both upper-layer NAS signaling and lower-layer signaling (e.g., MAC CE or DCI) may be used for the WTRU to receive the LMF-initiated request for an order. For example, one or more new PRS configurations may be received by the WTRU via NAS signaling, while enable / disable triggers may be received via MAC CE or DCI to enable / disable the new PRS configurations.

[0080] An LMF-initiated on-demand request may be transmitted to one or more RAN nodes (e.g., TRPs, gNBs, cells) to change a PRS configuration, including actions related to turning on / off or reconfiguring the PRS configuration at different granularities (i.e., resources, resource sets, frequency sets, beams, TRPs). In one example, an LMF-initiated on-demand request may be received by a WTRU to explicitly indicate the transmission of a PRS. Similarly, an on-demand request may be implicitly received by a WTRU when detecting the transmission of a PRS or when detecting any change in the PRS transmission in relation to the applied and / or available PRS configuration(s) at the WTRU. In another example, an LMF-initiated on-demand request may be received by a WTRU to initiate and / or change / update one or more PRS configurations. In such cases, the WTRU may, for example, change parameters associated with the PRS configuration (e.g., PRS resource / pattern, resource set) or enable / disable a pre-configured PRS configuration based on a received on-demand request. The WTRU may also send an indication acknowledging the reception and / or triggering of the indicated action in response to receiving the on-demand request.

[0081] An LMF-initiated on-demand request may be triggered based on information transmitted or requested by the WTRU during one or more LPP procedures, including, for example, capability transmission procedures, auxiliary transmission procedures, or location information transmission procedures. In such cases, an LMF-initiated on-demand request may be triggered based on location information or measurement reports transmitted by the WTRU, for example, during location information transmission procedures for WTRU-based and WTRU-auxiliary positioning.

[0082] In one embodiment, the WTRU may perform various actions when rejecting an LMF-initiated on-demand request. In one embodiment, the WTRU may receive an indication from the gNB to continue using the existing PRS configuration when an LMF-initiated on-demand request, which may have been triggered based on a triggering indication (e.g., a request or a measurement report) transmitted by the WTRU, is rejected. In this case, the indication received by the WTRU may be intended to notify the WTRU, for example, that no changes to the PRS configuration or PRS transmission are expected. Alternatively, the WTRU may implicitly detect the rejection of the LMF-initiated on-demand request when, for example, it continues to receive the existing PRS transmission without receiving any indication from the gNB, or when the existing PRS configuration continues to be used by the network for a predetermined (configured) duration when the WTRU transmits the triggering indication to the network.

[0083] In another solution, the WTRU may reject an in-demand request initiated by an LMF received when determining the non-compliance of a new / updated PRS configuration. In one example, the WTRU may be configured with at least one criterion for performing evaluation / testing of a PRS configuration, including measurements using the PRS configuration at one or more different particle size levels (e.g., resources, resource sets, frequency sets, beams, TRPs), and may reject the PRS configuration when the measurements (e.g., RSRPs) are below or above a threshold. The WTRU may also be configured with one or more authorization rules that may authorize, for example, the ability to reject the PRS configuration at least partially at different particle sizes. In such cases, when rejecting the PRS configuration, the WTRU may transmit a rejection indication to the network, possibly indicating the PRS configuration ID and / or the reason for rejection. Alternatively, the WTRU may implicitly reject the PRS configuration by not including certain measurement results associated with the PRS configuration when transmitting the measurement report.

[0084] In other embodiments, the WTRU may initiate an on-demand request for a PRS. In one embodiment of an on-demand PRS initiated by the WTRU, the WTRU may transmit an on-demand request to a network (i.e., a gNB or LMF within the RAN) to request the transmission of the PRS based on PRS configuration information received and available at the WTRU. The on-demand request transmitted by the WTRU may be applicable to both DL-PRS and UL-SRSp transmissions. Specifically, in the case of a DL-PRS, the WTRU may request the DL transmission of the PRS, whereas in the case of a UL-SRSp, the WTRU may request the activation / initialization of a UL-SRSp to be transmitted by the WTRU. The on-demand PRS initiated by the WTRU may include an ID and may be identified by the ID. The WTRU may transmit the on-demand PRS as a standalone message and / or, for example, include it in location information or measurement reports along with other messages (e.g., in an LPP procedure).

[0085] When the WTRU receives an initial PRS configuration via either an LPP auxiliary data transmission procedure or RRC signaling (e.g., broadcast or dedicated RRC signaling), it may transmit an on-demand request for the transmission of a PRS. For example, the initial PRS configuration received by the WTRU may include information on resources, resource sets, beam(s), frequency sets, or the granularity of TRP(s). In such cases, the on-demand request transmitted by the WTRU may be intended to request at least a portion of the initial PRS configuration within a given granularity. For example, the WTRU may transmit an on-demand request based on certain triggering conditions described elsewhere to request the transmission of a PRS from one or more TRPs by using one or more resource sets or by including TRP and / or resource set IDs in the request.

[0086] In other embodiments, the WTRU may initiate an on-demand request to change and / or update the PRS configuration. In one example of an on-demand PRS initiated by the WTRU, the WTRU may transmit an on-demand request to the network (i.e., a gNB or LMF within the RAN) to request an update / change to the PRS configuration. Changes to the PRS configuration may include requests for one or more of, for example, different resource densities, different periodicities, different PRS iterations, changes in frequency, or changes in beam configuration. When transmitting the on-demand request, the WTRU may receive the new / updated PRS configuration when the request is permitted by the network. The WTRU may subsequently use the new / updated PRS configuration to perform DL PRS measurements or UL-SRSp transmissions.

[0087] In one example, the WTRU may send an on-demand request when determining the suitability of the initial (e.g., first) PRS configuration received from the WTRU based on measurements performed by the WTRU. For example, the WTRU may perform measurements on the PRS received from a set of TRPs / gNBs in the initial PRS configuration. Subsequently, the WTRU may determine, based on the measurements, whether updated information related to the initial PRS configuration (e.g., changes in resources, resource sets, or TRPs) may be required. As an example, the WTRU may send an on-demand request to update the PRS configuration when determining that measurements made using the initial PRS configuration are below or above a predetermined configured threshold. In another example, the WTRU may include in the on-demand request information that may not be part of the initial PRS configuration but is detectable and measurable by the WTRU, such as resource information or TRP / gNB IDs. Likewise, the WTRU may indicate in an on-demand request a revised PRS configuration for pruning certain attributes (e.g., TRP / gNB) that may be part of the initial PRS configuration but may not be suitable for performing positioning measurements (e.g., the measured RSRP is below a threshold for a certain configured duration). Subsequently, the WTRU may receive the updated configuration after the RAN / LMF performs changes to the PRS configuration based on the on-demand PRS request transmitted by the WTRU (i.e., when reconfiguring the TRPs / gNBs indicated via NRPPa signaling).

[0088] In other embodiments, the WTRU may include information regarding the urgency level of the on-demand request. The WTRU may include information regarding the urgency level when transmitting the on-demand request to the PRS. Information regarding the urgency level may be related to one or more of the delivery of the on-demand request (i.e., to the LMF or gNB), the delivery of the updated PRS configuration to the WTRU, and the transmission of the PRS for measurement in the WTRU. In one example, the urgency level may be indicated by the WTRU in the form of timing information (e.g., time slots, number of slots from the start time slot). In another example, the urgency level may be indicated in the form of a priority value. The WTRU may be (pre-configured) with mapping rules to identify timing information and / or priority values ​​based on the urgency level for the delivery of the on-demand request, the updated PRS configuration, or the transmission of the PRS. The timing information or priority may be included in the on-demand request or in other messages transmitted before or after the on-demand request, and may include an ID associated with the on-demand request. In such cases, the WTRU may include a high priority value when sending an on-demand request to request, for example, an updated PRS configuration or a PRS transmission with high urgency and low latency.

[0089] In some embodiments, the WTRU may transmit one or more on-demand requests to trigger PRS configurations that may be pre-configured in one or more TRPs / gNBs / cells. PRS pre-configurations may include non-periodic, semi-continuous, or periodic PRS configurations. The WTRU may be represented by one or more PRS configurations that may be pre-configured in TRPs / gNBs / cells during or after an auxiliary data transmission procedure in which the WTRU may receive the associated PRS configuration. Upon receiving information indicating a mapping between the PRS configuration and the PRS pre-configuration IDs associated with the TRPs / gNBs / cell IDs, the WTRU may transmit an on-demand request for a non-periodic PRS, a semi-continuous PRS, or a periodic PRS based on the triggering conditions described herein. For example, the WTRU may send an on-demand request for an aperiodic PRS or a semi-persistent PRS to the associated TRP / gNB, directly or indirectly, by including the ID of the aperiodic PRS / semi-persistent PRS. The WTRU may send, for example, an on-demand request to request the transmission of an aperiodic PRS from the UCI and an on-demand request to request the transmission of a semi-persistent PRS from the MAC CE to the corresponding gNB.

[0090] In other embodiments involving network-initiated / triggered on-demand requests, the WTRU may be pre-configured with one or more PRS configurations (i.e., non-periodic, semi-continuous, periodic) and may receive an on-demand request to activate the pre-configurations for subsequent DL-PRS measurements or UL-SRSp transmissions. An on-demand request to activate one or more PRS configurations may include IDs associated with the PRS pre-configured in the WTRU. In some examples, the WTRU may receive an on-demand request to activate a non-periodic PRS pre-configuration at the DCI (PDCCH) and / or an on-demand request to activate a semi-continuous PRS pre-configuration at the MAC CE.

[0091] In another embodiment, when an on-demand request transmitted by the WTRU is rejected by the LMF / RAN, the WTRU may perform certain actions as described below. The WTRU may receive a rejection indication in an explicit message, such as in upper-layer signaling (i.e., NAS or RRC) or lower-layer signaling (MAC CE or DCI), in response to the on-demand request. Alternatively, the WTRU may implicitly receive a rejection indication when the following occurs: (1) after a certain time duration, the requested PRS transmission or the requested new PRS configuration is not received; or (2) the detection of something different from the requested PRS transmission or the reception of something different from the requested PRS configuration.

[0092] In these embodiments, when a rejection notice is received (explicitly or implicitly), the WTRU may perform one or more of the following actions. The WTRU may continue to use the existing PRS configuration (i.e., received during the auxiliary transmission procedure) until the next triggering condition is detected. The WTRU may retransmit an on-demand request upon the expiration of a prohibition condition (e.g., a timer, or the WTRU moving out of the restricted location). The WTRU may transmit an on-demand request including a request for a new PRS configuration that may differ from the previously rejected configuration. The WTRU may apply the new PRS configuration indicated in the rejection notice. The WTRU may fall back to a default PRS configuration that is pre-configured in the WTRU or that may be indicated in the received rejection notice.

[0093] In other embodiments, the WTRU may transmit on-demand requests directly or indirectly to the LMF / RAN. In one example, the WTRU may transmit on-demand requests to the LMF (e.g., in a NAS message via an LPP procedure) and / or to gNBs / cells within the RAN based on the association between the received PRS configuration and the LMF used for positioning services. In one example, the WTRU may use NAS signaling (e.g., via an LPP procedure) to transmit on-demand requests directly to the LMF. In this case, the NAS signaling may be returned from one or more Signaling Radio Bearers (SRBs) configured between the WTRU and the RAN. In another example, the WTRU may use RRC signaling, MAC CE, or physical uplink control channel (PUCCH) / UCI to transmit the on-demand request to the serving gNB / cell, and the serving gNB / cell may then encapsulate the on-demand request and forward it to the LMF via control plane (CP) or user plane (UP) signaling between the gNB and the LMF. In both examples, the on-demand request may include an identifier of the LMF associated with the PRS configuration that the WTRU applies for positioning. Alternatively, the WTRU may include an identifier of the RAN node when transmitting the on-demand request to a RAN node (e.g., gNB, TRP, cell) through the serving gNB / cell, and the serving gNB / cell may then forward the on-demand request within the RAN based on the identifier (e.g., via Xn signaling).

[0094] In other embodiments, the WTRU may transmit an on-demand request directly to the affected gNB. In one example, an on-demand request initiated by the WTRU may be transmitted directly or via an LMF to one or more serving gNBs / cells intended to apply a requested change in the PRS configuration or to trigger the transmission of the PRS using a new configuration. Specifically, the initial PRS configuration received by the WTRU may include association / mapping information for one or more gNBs / cells (i.e., gNB and / or cell IDs) to which the PRS may be transmitted from the DL or received from the UL (in the case of an SRSp). The association / mapping information may include certain selection rules / restrictions that may indicate gNBs / cells to which the WTRU may transmit an on-demand request directly to request a new PRS configuration or at least partially change an existing PRS configuration. In one example, a selection rule may indicate that a WTRU may be allowed to send an on-demand request to change / update a PRS configuration that affects only the serving gNB / cell. In this case, the on-demand request may be sent directly or indirectly (e.g., via an LMF) to the serving gNB / cell. In another example, a WTRU may be allowed to send an on-demand request to change / update a PRS configuration that affects one or more non-serving gNB / cells or neighboring gNBs / cells. In this case, the on-demand request may be sent indirectly through the serving gNB / cell or an LMF.

[0095] In another embodiment, the network may acknowledge the request and the content of the request. The WTRU may make a direct request (a request of the first type) or an indirect request (a request of the second type) for changing or adding PRS parameters based on the availability of the PRS configuration in the WTRU and / or measurement conditions (e.g., the RSRP of the received PRS is lower than the configured threshold). The WTRU may make the direct request or the indirect request by transmitting to the network a mark indicating a request to change and / or modify the PRS parameters. The WTRU may receive from the network a mark for using either the direct request or the indirect request to change and / or modify the PRS parameters. In some examples, the direct request or the indirect request may be referred to as an on-demand request. Hereinafter, the WTRU making a direct / indirect request may refer to the WTRU transmitting to the network a mark containing an on-demand request.

[0096] For example, if the WTRU receives configuration information for a number of PRS parameters (e.g., comb size, muting patterns, subcarrier intervals, or any PRS parameters described herein) from the network via LPP or RRC signaling, the WTRU may make a direct request for changes or new PRS parameters from a list of (pre)configured parameters.

[0097] Direct requests for PRS parameters made by WTRU may be selected from the aforementioned (pre)configured PRS parameters. Alternatively, WTRU may receive an explicit indication from the network (e.g., gNB or LMF) to send direct requests for updated / additional PRS.

[0098] An indirect request for an updated or additional PRS may be made by the WTRU under at least one of the following conditions: when (pre)configurations of the PRS parameters are not available in the WTRU; or when the WTRU receives an explicit indication from the network (e.g., gNB or LMF) to send an indirect request for an updated / additional PRS. The WTRU may receive an indication from the network, for example, indicating the quantity to be reported to the network in the indirect request. The content of the indirect request may depend on the positioning method implemented by the WTRU. For example, when the WTRU implements the Uplink Time Difference of Arrival (UL-TDOA) positioning method, the WTRU may not request changes or additions to the PRS parameters.

[0099] Examples of indirect requests for updates or new PRS parameters, i.e., on-demand PRS, may include at least one of the following.

[0100] A WTRU may include spatial information in an indirect request related to requesting a network (e.g., gNB or LMF) to transmit PRS(s) toward different directions. Examples of such indirect requests related to spatial information may be one of the following.

[0101] Indirect requests may include PRS resource ID(s) and / or PRS resource set ID(s) associated with SRSp resource ID(s) in spatial relationship information configured via RRC. The spatial relationship information may associate downlink (DL) RS / SRS and SRSp so that the WTRU can perform beam management / alignment. By including SRSp resource ID(s), SRS resource ID, PRS resource ID(s), or any DL RS / channel (e.g., SSB, CSI-RS) associated with SRSp resource(s) in the spatial relationship information, the WTRU may request the network to configure different PRS resource(s) (i.e., the WTRU may request the network to transmit PRS beams in different directions). The WTRU may request the network to transmit multiple PRS resources (i.e., beams) so that beam sweeping can be performed to find a beam that yields a satisfactory RSRP.

[0102] Indirect requests may include DL-RS resource ID(s) rather than PRS resource IDs. The WTRU may transmit CSI-RS resource IDs or SSB indices that are not part of the spatial relationship information. The WTRU may obtain directional information of the CSI-RS beam or SSB beam through MIMO communication or initial access and may request the network to find a PRS resource that is spatially aligned with the requested DL-RS resource.

[0103] Indirect requests may include RX beam indices or indices. The WTRU may include multiple RX indices in the request message so that the network can configure PRS resource(s) and / or set(s) of PRS resources that can be received by the RX indices transmitted by the WTRU.

[0104] Indirect requests may represent relative AoA. The WTRU may include an uncertainty window in relative AoA measured in degrees and an expected AoA. Relative AoA may be defined in relation to a reference point (e.g., lowest Rx beam index, Rx beam index = 0). The uncertainty window in relative AoA may be defined as a range of relative deviation from the expected relative AoA. For example, if the relative AoA is 30 degrees, the uncertainty window for relative AoA may be expressed as plus or minus 5 degrees, indicating that the relative AoA may vary between 25 and 35 degrees. The WTRU may report relative AoA to the LMF to help the LMF focus PRS beams centered around the expected AoA and spread them within the uncertainty angle range.

[0105] Indirect requests may represent AoA. Similar to relative AoA, WTRU may include an uncertainty window in AoA measured in degrees and an expected AoA. The uncertainty window in relative AoA may be defined as a range of relative deviation from the expected AoA. For example, if the AoA is 30 degrees, the uncertainty window for AoA may be expressed as plus or minus 5 degrees, indicating that the relative AoA may vary between 25 and 35 degrees. WTRU may report AoA to help LMF focus PRS beams centered around the expected AoA and diffuse within the uncertainty angle range.

[0106] Indirect requests can represent RSRPs (e.g., RSRP per RB or RSRP per configured number of RBs) with finer granularity. For example, at finer granularity, RSRPs can represent the presence of multipath, and the network can configure PRS beams transmitted from different directions.

[0107] In the case of one or more of the above requests related to spatial parameters, WTRU may receive additional or updated information regarding at least one of the following PRS parameters: TRP ID, PRS resource set ID, PRS resource ID having associated parameters (e.g., periodicity, comb value, muting pattern), and / or expected AoD and uncertainty (e.g., range of angles), expected reference signal time difference (RSTD) and uncertainty (e.g., time range).

[0108] Indirect requests related to temporal information may be made by WTRU to request the network (e.g., gNB or LMF) to transmit PRS(s) more frequently / less frequently.

[0109] An indirect request may indicate the number of opportunities to measure PRS that can be made by the WTRU. For example, if the WTRU cannot measure the PRS transmitted by the network due to collisions between the PRS and other downlink channels, the number of measured opportunities may be suggested to the network to increase the periodicity of PRS transmissions (i.e., PRS is transmitted less frequently), or the network may change the time offset for PRS transmissions so that collisions with other channels can be avoided.

[0110] In the case of WTRU-based positioning, indirect requests may represent location information with uncertainty. For example, if the uncertainty exceeds a pre-configured threshold in the network (e.g., LMF or gNB), the network may reduce the periodicity of PRS transmissions.

[0111] In the case of one or more of the above indirect requests related to temporal information, WTRU may receive changes or additions related to the following PRS parameters: muting patterns for PRS resource(s), symbol / slot offsets for PRS resource(s), and / or periodicity, repetition count, number of symbols, or resource time gaps for PRS resource(s).

[0112] In one embodiment, the following procedure is an example of sequences / steps that a WTRU may follow. 1. The WTRU receives conditions for making indirect request(s) for changing or adding one or more PRS parameters from the LMF. 2. The WTRU receives configuration information from the network and types of indirect requests that the WTRU may make or be allowed to request from the LMF (e.g., relative expected AoA and window of uncertainty, CSI-RS resource ID, or any of the quantities / parameters mentioned above). 3. The WTRU measures the RSRP of some of the PRS resource(s) where the RSRP of some of the PRS resource(s) may be below a configured threshold. 4. The WTRU reports the RSRP measurement to the network and includes the indirect request (e.g., relative expected AoA and window of uncertainty as described above) in the report. 5. The WTRU receives a WTRU-specific message (LPP message, DCI, MAC-CE) containing an indication from the LMF that new PRS resources configured via auxiliary data distributed by the network correspond to the configuration for the indirect request made by the WTRU, i.e., the on-demand PRS. 6. The WTRU receives the on-demand PRS and the PRS that the WTRU had received prior to making the indirect request.

[0113] In another embodiment, an acknowledgment from the network for a request from the WTRU is provided. The WTRU may receive an explicit acknowledgment or acknowledgment message from the network (e.g., from or through an LMF or gNB) in response to a request transmitted by the WTRU. The WTRU may receive the acknowledgment / acknowledgment in at least one of the following messages: an LPP configuration via LPP providing auxiliary data in which the LMF may indicate PRS resources configured for a request made by the WTRU; Uu signaling, such as a WTRU-specific configuration message in DCI, MAC-CE, or RRC in which the gNB may indicate PRS resources configured for a request made by the WTRU; and one or more of signals or configurations that are WTRU-specific, broadcast, or multicast. In one example, the WTRU may receive a PRS resource configuration with updated parameters from the network (e.g., an LMF or gNB). In this case, the WTRU may receive updated parameters from the network, for example, under the same PRS resource ID. In another example, the WTRU may receive different PRS resource(s) (e.g., PRS configurations with different resource IDs or resource set IDs) from a network (e.g., LMF or gNB). In another example, the WTRU may receive from the network an indication that a PRS configuration that the WTRU received a priori is disabled in order to make an on-demand request. Thus, the WTRU may report to the network (e.g., LMF) measurements made only for the on-demand PRS.

[0114] WTRU can assume that a request made by WTRU is accepted by the network and therefore expects to receive the requested PRS without receiving an acknowledgment in response to the WTRU request. In one example, there may be certain parameters or conditions associated with the requested PRS that may or may not allow WTRU to receive an acknowledgment indicating that the request made by WTRU is accepted by the network. The parameters or conditions may be related to or based on at least one of the following. WTRU may not need to receive an acknowledgment (from the LMF or gNB) for a request for certain parameters requested by WTRU, e.g., the comb size of the PRS, or a change in the resource offset. WTRU may need to receive an acknowledgment (from the LMF or gNB) for a request for certain parameters requested by WTRU, e.g., muting options, subcarrier interval, TRP ID, PRS resource ID, iteration count, and periodicity.

[0115] FIG. 3 is a signal flow diagram illustrating a procedure (300) for enabling on-demand and dynamic SRS. In FIG. 3, a positioning information request (308) may be provided to the gNB (304) via NRPPa from the LMF (306). The WTRU may transmit a reconfiguration / on-demand indication to the serving gNB to request to perform an RS transmission, such as an SRSp, based on the detection of one or more triggering conditions configured in the WTRU. The embodiments described herein may also be used to request the transmission of other types of RS. To determine the SRS configuration to be displayed in the on-demand indication, the WTRU may be configured with triggering conditions / criteria and mapping rules for mapping between the triggering conditions and the SRS configurations. The mapping rule may indicate that for each of the different SRS configurations identified by a configuration identifier (ID), there may be one or more associated triggering conditions that can be monitored and detected by the WTRU to determine the SRS configuration to be selected for ultimate transmission.

[0116] The WTRU may receive one or more SRS configurations and associated triggering conditions and mapping rules from the serving gNB (304) in either a dedicated RRC message or a broadcast RRC message (SIB) (310). Different triggering conditions and mapping rules received by the WTRU to determine the SRS configuration may include one or more combinations of events / parameters associated with the upper layer and / or access layer (AS) layer.

[0117] When dynamically determining an SRS configuration based on a trigger (312), the WTRU may transmit an on-demand indication to the network to indicate the selection and transmission of the SRS for positioning (314). The on-demand indication may be transmitted by the WTRU in any one of a UCI (e.g., SR), UL MAC CE, or RRC message. The content of the on-demand indication for the SRS may include one or more of a request for the SRS, a selected SRS configuration, a determined SRS configuration, and / or WTRU status information.

[0118] Using a request for SRS, for example, an indication transmitted by the WTRU may request the activation of SRS transmission for a pre-configured SRS resource configuration in the WTRU. For example, using a selected SRS configuration, the WTRU may indicate an identifier of the selected SRS configuration (314), which may be selected from a set of pre-configured SRS configurations based on configured mapping rules. For example, using a determined SRS configuration, the WTRU may indicate the configuration of the determined SRS configuration, which may be determined based on a configured formula / expression that can map between triggering conditions and SRS configurations. For example, using WTRU status information, the WTRU may indicate status information (e.g., WTRU speed, direction) related to events / conditions applicable to the WTRU, which may be identified based on configured triggering conditions. In this case, the selection of the SRS configuration may be performed by the network based on the indicated WTRU status information.

[0119] Subsequently, the WTRU may receive an activation message (316) from the network indicating the activation of a selected SRS configuration, wherein the selected SRS configuration may correspond to information included in an on-demand SRS indication transmitted by the WTRU. An activation message for enabling the transmission of the SRS may be received by the WTRU in any one of a DCI, DL MAC CE, or RRC message and may include an identifier associated with the selected SRS configuration. In one example, the WTRU may perform the transmission of the SRS (318) upon receiving an activation message containing the selected SRS configuration. In another example, the WTRU may initiate the transmission of the SRS using the SRS configuration selected by the WTRU when transmitting an on-demand SRS indication.

[0120] Some of the advantages obtained from the above methods may include reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0121] When trigger conditions are satisfied, the WTRU may decide to transmit a request for a PRS or SRS for positioning with different parameters. The parameters may include at least one of the following: the number of symbols for the SRS for positioning; the transmit power for the SRS or PRS; the number of SRS or PRS resources included in the SRS resource set or PRS resource set, respectively; a muting pattern for the PRS; for example, the muting pattern may be represented as a bitmap; muting options for the PRS (e.g., from the literature [3GPP, "LTE Positioning Protocol (LPP)," TS 37.355, ver. 16.0.0, March 2020]); Option 1 or Option 2; periodicity for the PRS or SRS for positioning; the type of the PRS or SRS: periodic, semi-continuous, or non-periodic; a slot offset for periodic transmission for the PRS or SRS for positioning; Vertical shift of the PRS or SRS pattern in the frequency domain; time gap during repetition for the PRS or SRS for positioning; repetition factor for the PRS or SRS for positioning; RE offset for the PRS or SRS for positioning; comb pattern for the PRS or SRS for positioning; spatial relationship; TRP ID; absolute radio-frequency channel number (ARFCN); subcarrier spacing; expected RSTD, uncertainty at expected RSTD; start PRB; bandwidth and / or BWP ID of the PRS or SRS.

[0122] In one embodiment, the parameters may be reconfigured based on a request from the WTRU. The parameters may be included in a list of parameters, and the WTRU may request the network to reconfigure them. The WTRU may transmit the request to the network once the triggering conditions for the request are satisfied. If multiple triggering conditions exist, the WTRU transmits the request to the network once the triggering conditions are satisfied. For example, if the measured RSRP corresponding to the PRS is lower than a threshold, the WTRU may transmit a request to the network to change the periodicity so that a denser PRS in the time domain can be received by the WTRU.

[0123] In another example, the WTRU can send a request to the network to reconfigure the spatial relationship between the uplink RS and the downlink RS. For example, if the measured RSRP is low, the WTRU can send a request to the network to change the spatial relationship between the SRS for positioning and the downlink RS, or between channels such as CSI-RS, PRS, or SSB. For example, the number of resources for either the target RS or the reference RS can be changed according to a request from the WTRU. This is equivalent to changing the direction of the UL transmit beam to maximize the received SNR.

[0124] In one method, a request for the reconstruction of one or more of the parameters may be associated with measurements explicitly or implicitly reported by the WTRU. For example, the WTRU may include a request for the reconstruction of the transmit power in a measurement report for the RSRP. The WTRU may receive one or more conditions for one or more reconstructions. The WTRU may transmit the measurement report and determine the parameters for the reconstruction. For example, the WTRU may know that once the RSRP measured by the WTRU is lower than a threshold, the network can reconstruct the transmit power of the PRS. Thus, the WTRU may transmit the measurement report for the RSRP and anticipate an update to the transmit power for the PRS. The gNB may perform SRS measurements (320) and provide an NRPPa message (322) containing the measurement report to the LMF (306).

[0125] In one embodiment, WTRU may receive a list of sets of PRS parameters from LMF, wherein each set consists of the aforementioned PRS parameters (e.g., comb values, number of symbols, repetition factor, periodicity, PRS resource ID, PRS resource set ID, bandwidth). WTRU may select a certain set from the configured list of sets of parameters and decide to make a request once one or more triggering conditions are satisfied.

[0126] Each set of PRS parameters can be associated with an identification number. When a triggering condition is satisfied, the WTRU can send a request to the LMF, indicating the identification number for the requested set of PRS parameters. By transmitting the ID for the set of PRS parameters, the overhead for signaling between the WTRU and the network can be reduced.

[0127] One or more different set(s) may be associated with different triggering condition(s). For example, the WTRU may receive multiple thresholds from the LMF, such as RSRP thresholds a1 and a2 where a1 > a2 in one embodiment. For example, if the WTRU receives two sets of PRS parameters from the LMF, the WTRU may send a request for PRS parameter set 1 if the lowest RSRP among the PRS received from the serving gNB and / or neighbor gNBs is less than the RSRP threshold a2. The WTRU may send a request for PRS parameter set 2 if the lowest RSRP among the PRS received from the serving gNB and / or neighbor gNBs is greater than the RSRP threshold a2 but less than a1. The WTRU may not send a request for PRS reconfiguration if the lowest RSRP among the PRS received from the serving gNB and / or neighbor gNBs is greater than a1.

[0128] The metrics used by WTRU to determine the set of PRS parameters may not be limited to the lowest RSRP among PRS received from serving gNBs or neighboring gNBs. Examples of metrics are as follows: lowest / highest RSRP among PRS received from serving gNBs and / or neighboring gNBs; average RSRP across time / TRPs / gNBs of PRS received from serving gNBs and / or neighboring gNBs; standard deviation / range / variance of RSRPs of PRS received from serving gNBs and / or neighboring gNBs.

[0129] Each set of PRS parameters may include different combinations of values ​​for the PRS parameters. For example, using the example described above, parameter set 1 may include parameters having a greater number of symbols and repetition factors than parameter set 2 so that the WTRU can acquire more measurements in the time domain to achieve more accurate positioning.

[0130] Each set of PRS parameters may be associated with a TRP / gNB / panel or a PRS transmission source. By requesting a set ID, the WTRU may equivalently request a PRS transmission from a source ID (e.g., TRP ID) having PRS parameters (e.g., number of symbols, repetition factor, bandwidth, comb values) associated with the set ID (which is also associated with the source ID).

[0131] Each set of PRS parameters can be associated with a PRS resource set ID, wherein the set includes a subset / one set of PRS parameters from the associated PRS resource set ID. The WTRU consists of multiple subsets of PRS parameters having subset IDs associated with the PRS resource set ID, and can request the LMF to construct new PRS parameters by indicating the set ID and the subset ID.

[0132] The WTRU may determine the PRS and / or SRSp configuration based on triggering parameters. In this embodiment, the WTRU may determine the PRS and / or SRSp configuration or request a change in the PRS and / or SRSp configuration using one of the following parameters or any combination thereof: WTRU velocity; measurements; measurements related to integrity; metrics related to integrity regarding positioning, e.g., alarm limit for issuing an alarm, alarm time which is the duration while an acceptable limit is reached and no alarm is issued, integrity risk which is the probability that a positioning error will exceed the alarm limit, protection level which is a statistical boundary for positioning errors, error tolerance level; recovery time, e.g., time required by the system to recover from a positioning failure; integrity alarm; response time; WTRU acceleration; traffic / LCH priority; direction of WTRU movement; Doppler shift; Doppler spread; delay spread; mean delay; number of multipaths; arrival time of the reference signal; departure time of the reference signal; difference between the arrival time and departure time of the reference signal; Time difference of arrival (TDOA); timestamp (based on either internal or global clock); integrity; alerts; K-factors in fading channels; traffic status; DRX status; time for inactivity; RSRP; channel ranks; QCL types; RNTI; and / or data becoming available for transmission to a logical channel, or the amount of data available for transmission to a logical channel becoming higher than a threshold.

[0133] WTRU can first determine its preferred PRS and / or SRSp configuration based on one or any combination of the above parameters. Subsequently, WTRU can transmit a request for the preferred configuration to the network. In one approach, WTRU can be (pre-)configured with a certain range of parameters for a PRS and / or SRSp configuration. Subsequently, WTRU can determine the PRS and / or SRSp configuration based on one or more values ​​of these parameters and the associated PRS and / or SRSp configuration.

[0134] In one embodiment, WTRU is (pre-configured) with two possible SRSp configurations associated with its speed. WTRU may use the first SRSp configuration if its speed is less than a threshold. Otherwise, it may use the second SRSp configuration. Subsequently, WTRU may transmit a request according to the SRSp configuration based on its speed. The speed threshold may be (pre-configured). For example, WTRU may request an SRSp configuration if its speed becomes greater than the threshold, or if its speed becomes less than the threshold.

[0135] Some of the advantages obtained from the above methods may be reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0136] One or more positioning methods may be used by the WTRU, wherein the positioning methods may include one or more of the following: Network Assisted Global Navigation Satellite System (GNSS); Observed Time Difference Of Arrival (OTDOA); Barometric Sensor Positioning; WLAN Positioning; Bluetooth Positioning; TBS Positioning; Motion Sensor Positioning; DL-TDoA; UL-TDoA; Multi-cell RTT; DL-AoD; and / or UL-AoA.

[0137] The positioning signal may be a reference signal or a GNSS signal, which is used for positioning, and may be used interchangeably with a PRS, an SRS for positioning (SRSp), a beam reference signal, a tracking reference signal, a ranging signal, a side-link positioning reference signal, and a measurement signal.

[0138] In one embodiment, one or more positioning methods may be used in WTRU, and WTRU may determine to trigger a request to a network (and / or positioning server) when one or more predefined conditions are met.

[0139] In one embodiment, one or more positioning methods may be configured, determined, or used for the WTRU, and the first positioning method may be based on a positioning reference signal from a cellular network (e.g., PRS, SRS for positioning), and the second positioning method may be based on a GNSS signal. The WTRU determines the availability, detectability, measurement quality, and / or accuracy of the GNSS signal and may request a positioning reference signal from the network (or positioning server). The WTRU may determine the availability of the signal (e.g., GNSS signal or PRS) for the positioning method based on the energy detection of the signal. For example, if the energy of the received signal is below a threshold, the WTRU may determine that the signal is not available or not detectable. WTRU can determine the measurement quality of a signal (e.g., GNSS signal or PRS) for a positioning method based on one or more thresholds of measurement, wherein the measurement may include RSRP and SINR. WTRU can determine the accuracy of a signal (e.g., GNSS signal or PRS) based on the positioning accuracy of a positioning method (e.g., within x meters).

[0140] In another embodiment, the WTRU may use or be composed of a first positioning method, which is a non-GNSS-based positioning method, and a second positioning method, which is a GNSS-based positioning method, wherein the WTRU may determine whether the non-GNSS-based positioning method uses or does not rely on the availability, detectability, measurement quality, and / or accuracy of the GNSS-based positioning method. If the second positioning method is below the required or predefined quality (e.g., not available, not detectable, or not accurate), the WTRU may trigger a request for the first positioning method. If the second positioning method exceeds the required quality (e.g., available, detectable, or accurate), the WTRU may transmit an indication to the gNB to disable the configuration of the first positioning method. A battery level may also be used to determine whether the GNSS-based positioning method can be used.

[0141] In another embodiment, the WTRU may use or be composed of a first positioning method (e.g., Downlink Time of Arrival Difference (DL-TDoA)) which may be based on a downlink positioning signal (e.g., PRS) and a second positioning method (e.g., UL-TDoA) which may be based on an uplink positioning signal (e.g., SRS for positioning). The WTRU may determine one of the positioning methods based on the availability, detectability, measurement quality, and / or accuracy of the positioning signal for the first positioning method. If the first positioning method is below the required or predefined quality, the WTRU may begin transmitting the uplink positioning signal from a determined uplink resource (e.g., preconfigured, indicated). If the first positioning method is required or exceeds a predefined quality, the WTRU may stop transmitting the uplink positioning signal.

[0142] WTRU can indicate the status of the positioning method (e.g., active, inactive) to the network (or positioning server).

[0143] Some of the advantages obtained from the above methods may include reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0144] In other embodiments, when certain triggering conditions are satisfied, the WTRU may perform a WTRU-initiated on-demand request for a PRS. In some examples, the WTRU may transmit an on-demand PRS to the LMF and / or RAN based on one or more of the triggering conditions described herein. Based on the WTRU's ability to transmit an on-demand PRS, additional triggering conditions configured (pre-)in the WTRU by the LMF and / or RAN (e.g., via LPP procedures) and RAN (e.g., via RRC signaling) may include the following.

[0145] Upper-level indicators or triggers may be used. For example, an on-demand PRS request may be transmitted when the WTRU receives an upper-level indicator from the WTRU (e.g., in the case of WTRU-initiated positioning, MO-LR) or from the network (e.g., in the case of LMF-initiated positioning, MT-LR). In one example, the WTRU may, in the on-demand request, use at least partially the same content received from the upper-level request, possibly including information related to the PRS configuration. In another example, the WTRU may use mapping rules to determine the content to be included in the on-demand request based on the information received from the upper-level request.

[0146] Event triggers based on measurements made for a received PRS configuration may be used in other examples. For example, a PRS configuration may be associated with one or more measurement thresholds, which may be configured for any of the following measurement attributes: resources, resource sets, frequency sets, beams, and / or TRPs / gNBs. Additionally, a measurement profile / pattern consisting of measurement attributes and time durations for performing measurements may also be configured in the WTRU. The WTRU may send an on-demand request to the PRS when measurements made using the configured profile are higher or lower than certain (configured) thresholds.

[0147] Event triggers based on WTRU mobility can be used in other examples. For example, WTRU can send an on-demand request when detecting a new cell ID that may be inside or outside the PRS configuration used by WTRU during mobility.

[0148] Event triggers based on measurements made in non-positioning related configurations may be used in other examples. For example, an on-demand request to change / update the PRS configuration may be sent when the WTRU detects triggering conditions associated with the radio link(s) (e.g., Uu links) associated with the initial PRS configuration. Triggering conditions associated with the radio links may include radio link failure / recovery and / or conditions related to data transmissions (e.g., the number of ARQ / HARQ retransmissions) that may affect positioning-related measurements when using any part of the PRS configuration. For example, the WTRU may send an on-demand request to remove a TRP or beam from the PRS configuration when it detects an RLF for a TRP or detects a beam failure.

[0149] Finally, periodic or timer-based mechanisms may be used in other examples. For instance, periodic transmission using configured periodicity may be used. In another example, when the timer expires since the last transmission of an on-demand request to the PRS, another on-demand request to the PRS may be transmitted.

[0150] In other embodiments, the WTRU may transmit an on-demand request for a PRS based on the type of received PRS configuration. In one example, the type or format applied by the WTRU when transmitting an on-demand request for a PRS may vary based on the type of the requested PRS. Specifically, the WTRU may be composed of one or more PRS configurations of different types, including aperiodic configurations, semi-persistent configurations, and periodic configurations. For different PRS configurations, the WTRU may also be composed of signaling of an associated type / format to be applied when transmitting an on-demand PRS request. The WTRU may include identifier(s) associated with the PRS configuration and the type of configuration in the on-demand request. The following examples illustrate the association between the type of signaling that returns an on-demand request and the type of the PRS configuration to request the transmission of a PRS or to change a PRS configuration. The WTRU may use PUCCH / UCI to request the transmission of an aperiodic PRS or a new aperiodic PRS configuration. Alternatively, the WTRU may use MAC CE to request the transmission of a semi-continuous PRS or a new semi-continuous PRS configuration. Alternatively, the WTRU may use RRC / NAS signaling to request the transmission of a continuous PRS or a new continuous PRS configuration.

[0151] In another example, the WTRU can flexibly change the signaling type for sending an on-demand request to a PRS based on the latency / urgency and / or positioning service QoS requirements / class associated with the request. For example, the WTRU may use a UCI or MAC CE to send an on-demand request intended for the transmission of a persistent PRS when triggered by certain associated conditions (e.g., higher-level requests, priority) to change the signaling type.

[0152] In one embodiment, the WTRU autonomously determines the SRSp configuration. In this example, for simplicity, the SRS for positioning is denoted as SRSp. The WTRU may be composed of one or more SRSp configurations, and the WTRU may determine a subset of SRSp configurations (e.g., one SRSp configuration) for SRSp transmission. One or more of the following may be applied.

[0153] An SRSp configuration may include or represent at least one of the following: an associated path loss reference signal; time / frequency density (e.g., comb, number of symbols, slot numbers); start symbol; frequency offset; sequence-id; spatial relationship information; frequency hopping information; sequence group hopping information; resource type (e.g., aperiodic, periodic, semi-persistent).

[0154] WTRU can determine a subset of SRSp configurations (e.g., one SRSp configuration for SRSp transmission) based on at least one of the following: WTRU mobility, signal strength of the line of sight (LoS) path; frequency selectivity; availability, accuracy, or measurement quality of the GNSS signal; quality measurement of the associated path loss reference signal; and / or power headroom level.

[0155] Regarding WTRU mobility, for example, one or more SRSp configurations may be used, and each SRSp configuration may be associated with WTRU velocity (e.g., Doppler frequency). Regarding signal strength of the line of sight (LoS) path, the signal strength of the LoS path may be determined based on the power ratio between the first path of the positioning signal and the remaining paths. Regarding the measurement quality of the associated path loss reference signal, for example, if the path loss of the associated path loss reference signal is measured, the SRSp configuration may be excluded from a subset or excluded from SRSp transmission. Regarding power headroom levels, for example, if the WTRU is power-limited (e.g., low power headroom), the WTRU may determine one or more SRSp configurations with a higher time / frequency density. Otherwise, the WTRU may determine an SRSp configuration with a lower time / frequency density.

[0156] The WTRU can transmit the determined SRSp configuration information to the serving gNB (or positioning server). The determined SRSp configuration may be indicated via an uplink channel or signal (e.g., Physical Random Access Control Channel (PRACH), PUCCH, Physical Uplink Shared Channel (PUSCH), or SRS).

[0157] In one embodiment, one or more PRACH resources may be configured, and each PRACH resource may be associated with an SRSp configuration. The WTRU may transmit the PRACH resource associated with the determined SRSp configuration. When the WTRU receives an acknowledgment from the network (e.g., a random access response (RAR) corresponding to the transmitted PRACH resource), the WTRU may initiate transmission based on the determined SRSp configuration. Until the WTRU receives an acknowledgment, the WTRU may use the previously determined SRSp configuration.

[0158] In another embodiment, the WTRU may transmit an index of the determined SRSp configuration via PUCCH or PUSCH. When the WTRU receives a certain configuration from the network (e.g., an acknowledgment (ACK) for PUSCH, a new transmission of PUSCH, an acknowledgment from an upper layer including MAC-CE or RRC), the WTRU may begin using or transmitting the SRSp based on the determined SRSp configuration.

[0159] An uplink channel or signal for transmitting the determined SRSp configuration information may be determined based on the WTRU state, where the WTRU state may include an RRC state (e.g., RRC connected, RRC idle, or RRC inactive) and a DRX state (active or inactive).

[0160] In one embodiment, the WTRU may use PUCCH or PUSCH to transmit the determined SRSp configuration information when the WTRU is in an RRC connection state; otherwise, the WTRU may use PRACH to transmit the determined SRSp configuration information.

[0161] The SRSp configuration of this specification is used interchangeably with SRSp pattern, SRSp density, SRSp periodicity, and SRSp structure, but may still be consistent with the present invention. In this specification, the determination of the SRSp configuration may be referred to as an indication of a preferred SRSp configuration for a gNB (or positioning server).

[0162] In one embodiment, the WTRU may be composed of one or more PRS configurations, and the WTRU may determine a subset of PRS configurations (e.g., a certain PRS configuration) to be used for positioning measurements.

[0163] The PRS configuration may include at least one of the following: a repetition factor; a resource time gap; the number of symbols; a muting pattern; resource power; an RE offset and / or a symbol offset.

[0164] The WTRU may determine a subset of PRS configurations based on one or more of the following: WTRU mobility; channel condition(s); availability, accuracy, or measurement quality of the GNSS signal; measurement quality of the PRS; and / or dynamic indication. For example, one or more PRS configurations may be used, and each PRS configuration may be associated with the WTRU velocity (e.g., Doppler frequency). Channel conditions may correspond to the signal strength or frequency selectivity of the LoS path. Regarding the measurement quality of the PRS, for example, if the PRS measurement is below a threshold, the PRS configuration may be excluded from the subset or excluded for positioning measurements. Using dynamic indication, for example, the WTRU may be configured with one or more PRS configurations via upper-level signaling (e.g., RRC and / or MAC-CE), and one of the configured PRS configurations may be dynamically indicated (e.g., via MAC-CE and / or DCI).

[0165] WTRU can transmit positioning measurement information for a determined PRS configuration having a PRS configuration identity. For example, each PRS configuration can be associated with a PRS configuration identity, and WTRU can report the associated PRS configuration identity when a positioning measurement is reported.

[0166] The SRSp configuration of this specification is used interchangeably with the PRS configuration, but can still be consistent with the methods described.

[0167] Some of the advantages obtained from the above methods may be reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0168] In some embodiments, the WTRU may be (pre-configured) with a plurality of PRS / SRSp configuration(s), each configuration being associated with a type of service. For example, a first configuration may be associated with a URLLC type service, and a second configuration may be associated with an eMBB type service. A WTRU that supports both services simultaneously may be configured to use the first configuration (i.e., to measure the PRS or transmit the SRSp of the first configuration) when positioning is requested for a URLLC type service. The second configuration may be used when positioning is requested for an eMBB type service.

[0169] In another embodiment, the WTRU may be (pre-configured) with a plurality of PRS / SRSp configurations, each configuration being associated with a set of active SCell(s). For example, the WTRU may be composed of four secondary cells that can be dynamically enabled / disabled. The WTRU may be composed of a first PRS / SRSp configuration that can be used when the first and second SCells are enabled, and a second PRS / SRSp configuration that can be used / assumed when the third and fourth SCells are enabled.

[0170] In some embodiments, when the WTRU is (pre-)configured with multiple PRS / SRSp configurations, the WTRU may be configured to select a configuration and to display the selected configuration to the network. Such display may be transmitted to the gNB using the new UCI format. Alternatively, the WTRU may implicitly display the selected configuration to the gNB using uplink resources associated with the PRS configurations. For example, a first PRS configuration is associated with a first PUCCH resource for reporting measurements, and a second PRS configuration is associated with a second PUCCH resource for reporting measurements. The WTRU may be configured to request / display the selected configuration to the network prior to measurement / transmission. Or, the WTRU may be configured to display the selected configuration to the network when it is reporting measurements of the PRS. For example, the WTRU is configured with two PRS configurations: one PRS configuration for a URLLC type service and another PRS configuration for an eMBB type service. The PRS signals of both configurations can be broadcast by the gNB without needing to request the network to transmit them. When the WTRU is triggered to report its position for a URLLC type service, the WTRU starts measuring the PRS signals of the PRS configuration associated with the URLLC type service and reports the measurements.

[0171] Some of the advantages obtained from the above methods may be reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0172] Details of lower-level signaling for triggering requests for reconfiguration are described herein. The WTRU requests a positioning reference configuration using lower-level signaling messages. In one approach, the WTRU may use one or any of the following transmissions to request a positioning reference signal configuration (either a PRS configuration or an SRSp configuration) and / or a measurement gap (MG) configuration: uplink control information such as a reference signal request (RSR); SR; MAC CE (e.g., BSR); and / or RRC messages.

[0173] The WTRU may transmit uplink control information to request RS configurations and / or MR configurations, such as PRS and / or SRSp configurations. This may also be used for requests of other types of RS. Such uplink control information may be referred to as a Reference Signal Request (RSR) in the following description. An RSR may be transmitted via PUCCH using PUCCH resources similar to those used for SRs in existing systems, multiplexed with other UCIs via PUCCH resources, and / or multiplexed with upper-layer data via PUCCH. The WTRU may use certain PUCCH resources from the set of PUCCH resources configured for SRs for the transmission of the RSR. Alternatively, the WTRU may use SRs to request RS configurations and / or MG configurations. The terms SR and RSR may be used interchangeably in the following description.

[0174] A WTRU can trigger an SR to request PRS and / or SRSp configurations and / or MG configurations. In one approach, the WTRU can be (pre-)configured to request PRS and / or SRSp configurations and / or MG configurations using a dedicated SR. In this case, the arrival of discovery data and / or MG requests may trigger the SR but may not trigger the transmission of a MAC CE (e.g., SL BSR). In another approach, the WTRU can be composed of multiple SR resources / configurations. Each SR resource / configuration may be associated with one or any combination of the following: PRS and / or SRRS configurations; parameters and / or ranges of parameters used to trigger PRS and / or SRSp configuration requests; and / or one or more MG configurations.

[0175] For example, WTRU can request a PRS configuration using a first SR resource, and it can request an SRSp configuration using a second SR resource. For example, WTRU can request a first MG configuration using a first SR resource, and it can request a second MG configuration using a second SR resource.

[0176] WTRU may trigger the transmission of an RSR based on at least one trigger condition described herein. WTRU may determine at least one RSR configuration including triggering parameters for the transmission of such an RSR. For example, if the RSR is triggered by data that becomes available on (or exceeds a threshold) a logical channel, WTRU may determine the identity of the logical channel and the threshold from such configuration.

[0177] Once the RSR is triggered, the WTRU may determine an RSR resource for transmission, such as a first available resource in the time resource. The WTRU may start a counter and start a timer. The WTRU may complete the procedure for transmitting the RSR when at least one of the following occurs: the WTRU receives an RS configuration applicable by the upper layers; the WTRU receives an enable command from the gNB via the DCI or MAC CE for an applicable RS (e.g., one-shot transmission or semi-continuous transmission / reception of the RS); or the WTRU receives a notice via upper layer signaling (e.g., RRC or MAC CE) that an applicable RS configuration may not be provided.

[0178] The WTRU can determine which RS is applicable from the configuration associated with the RSR. Such configuration may be provided by upper layers. When the WTRU completes the procedure, the timer may be stopped and the counter may be reset. The WTRU may start a second timer (e.g., a prohibition timer). The WTRU may trigger the RSR procedure under the condition that the prohibition timer is not running. The duration of the prohibition timer may be provided in a notification from the network or configured by upper layers regarding the RSR configuration.

[0179] The WTRU may retransmit the RSR on the first available resource upon the expiration of the timer. Depending on the maximum transmission power, the WTRU may increment the counter by, for example, a power step and increase the transmission power for the SR. When the counter reaches a threshold, the WTRU may complete the procedure and start a prohibition timer.

[0180] The WTRU may trigger the transmission of a MAC CE for a reference signal request and / or an MG configuration request based on at least one trigger condition described herein. The WTRU may start a timer (e.g., a prohibition timer) at the time of triggering, at the time of transmission of the MAC CE, or at any of the events described in the paragraph above (e.g., reception of an applicable RS configuration, activation of an applicable RS, or notification by upper-level signaling). The value of the prohibition timer may be configured by the upper level for each applicable trigger, or may be received from signaling from the network after the transmission of the MAC CE. The WTRU may not trigger the transmission of the MAC CE for a reference signal request while the prohibition timer is running.

[0181] Some of the advantages obtained from the above methods may be reduced end-to-end latency for positioning and configuration, improved positioning accuracy, and reduced overhead for configuration.

[0182] In some embodiments, the WTRU may be configured to support integrity-related requirements. To support integrity-related requirements, the WTRU may receive configuration information from the RAN regarding application / upper-layer functions or location service (LCS) functions, e.g., positioning error tolerance levels and error calculation metrics. To determine positioning errors, the WTRU may access alternative positioning information of the WTRU determined using different positioning methods. (2) Alternative positioning information may be independent of (1) positioning information determined using PRS / SRS-based measurements, such as RAT-independent methods. Alternative positioning information may be used to improve the reliability level of the positioning information and to verify the determined positioning information. For example, the WTRU may acquire both RAT-dependent and GNSS-based positioning information to verify the positioning information and to improve its accuracy / accuracy. In another example, redundant positioning information having either the same level of accuracy or a different level of accuracy may be obtained by using different positioning methods and may be used to verify positioning information and improve its reliability level. In an example related to network secondary integrity, the WTRU may receive alternative positioning information from the RAN and / or LMF. The alternative positioning information received from the RAN / LMF may be determined, for example, based on measurements of different SRSp configurations transmitted by the WTRU. In an example related to WTRU secondary integrity, the WTRU may determine alternative positioning information using other RAT-independent positioning methods, such as GNSS or WLAN.

[0183] In some embodiments, the WTRU may be configured to support recovery to an expected positioning action (e.g., positioning accuracy is within an acceptable error level) when a potential positioning failure condition (e.g., positioning accuracy is outside an acceptable error level) is detected. For example, recovery to an expected positioning action may be beneficial in safety-related use cases (e.g., guidance vehicles), where it is essential to ensure that the determined positioning information always remains within an acceptable error level during operation. To enable recovery from a positioning error, a recovery time duration may be provided along with the positioning error tolerance level and configured in the WTRU (e.g., in auxiliary information). In this case, the recovery time duration may be considered a requirement associated with integrity. The recovery time duration may be application-dependent. For example, in the case of automated guidance vehicles that transport assets in a factory, recovery time and associated actions (e.g., pausing until the correct position is acquired) may require strict requirements for recovery time. When a positioning error corresponding to a configured tolerance level is detected by the WTRU, a procedure to correct the positioning error may be triggered within the recovery time duration. For example, in the case of network-assisted integrity for recovery, the WTRU may receive a trigger to use different configurations for the PRS / SRS and an indication of the detection of a positioning error from a serving gNB within the RAN. Similarly, in the case of WTRU-assisted integrity, the WTRU may indicate the detection of a positioning error and send a request to a serving gNB within the RAN to use a different positioning method or a different configuration for the PRS / SRS.When recovery to the expected positioning action is not possible within the recovery time duration, alarm / warning messages are generated and can be transmitted by the WTRU to an LMF in the RAN or network or to a higher-level function in the WTRU to indicate a positioning failure condition.

[0184] In one embodiment, the WTRU transmits a request for a PRS along with information used to help the LMF coordinate a PRS transmission. In the downlink-based positioning methods or downlink and uplink-based positioning methods described herein, a request from the WTRU for a new PRS configuration may include any of the following information. The following information may be used to identify the origin, cell ID, global cell ID, and / or TRP ID of the PRS transmission.

[0185] Due to low RSRP, the WTRU may request increased periodicity, TX power, or frequency of the transmitted PRS sent from a specific cell or TRP. Thus, including the identification information may help the LMF coordinate the PRS transmission. Additionally, the WTRU may send a request to the LMF to change the beams or time offsets from a specific TRP or cell.

[0186] The WTRU may send a request for a PRS to the LMF along with a cell ID and optionally an LOS / NLOS indication. Such a request may be used to notify the LMF of unexpected changes in the environment. For example, the LMF may configure a PRS assuming the existence of an LOS condition between the TRP and the WTRU where the PRS is transmitted. However, the LOS may be blocked by an unexpected event. Therefore, the WTRU reports an NLOS to the LMF and a request for a different PRS configuration. The WTRU may report the absence of an LOS when the RSRP is lower than a predetermined threshold.

[0187] The WTRU can send a request to the LMF to turn off PRS transmissions. For example, the WTRU receives PRSs from different floors of a building. In such a situation, the WTRU may experience too much interference. Therefore, the WTRU can send a request to turn off or mute PRSs transmitted from a specific source.

[0188] In another embodiment , On-demand PRS is used for downlink and / or uplink-based positioning. . In this embodiment, the WTRU may transmit on-demand requests for PRS and / or SRSp configurations when supporting a DL&UL-based positioning method (e.g., multiple RTT). In DL&UL-based positioning, the WTRU and RAN determine measurements related to the time difference between the reception of the PRS and the transmission of the SRSp. Subsequently, the position of the WTRU may be determined as a function of the time difference measurements for the positioning RS and RTT to traverse between the WTRU and multiple TRPs / gNBs.

[0189] In WTRU-assisted positioning using the DL&UL positioning method, the WTRU can initially be configured with a PRS configuration by the LMF (via LPP) and an SRSp configuration by the RAN (via RRC). Subsequently, when the WTRU receives an activation trigger from the network, it can transmit an SRSp from the UL and measure the PRS received from the DL. Subsequently, the WTRU can determine the time difference between receiving the PRS and transmitting the SRSp from multiple TRPs / gNBs and transmit the measurement report to the LMF to determine the WTRU position. Similarly, in WTRU-based positioning using the DL&UL positioning method, the WTRU can initially request PRS and SRSp configurations when receiving a trigger from upper layers / applications to determine WTRU positioning information. Next, the WTRU transmits SRSp from the UL and can measure PRS received from the DL from multiple TRPs / gNBs. Then, the WTRU can receive measurement reports from the RAN, which are used to determine WTRU positioning information.

[0190] DL&UL-based positioning methods may result in higher latency due to the transmission of both PRS and SRSp and in determining time differences in both the WTRU and RAN. Additionally, when PRS / SRSp configurations are applied and measured in different TRPs / gNBs, higher latency may exist due to changes in PRS and / or SRSp configurations. In such cases, the WTRU may not be suitable for accurately determining WTRU positioning information. In these scenarios, the WTRU can assist in selecting / determining PRS and / or SRSp configurations by transmitting on-demand requests for PRS / SRSp based on different triggering conditions that can be configured in the WTRU. The on-demand request may include a request for specific PRS / SRSp configurations, a selection of PRS / SRSp, or an indication to change one or more parameters (e.g., resources, beam on / off) in the PRS / SRSp configurations.

[0191] The WTRU may decide to transmit an on-demand request for PRS configuration and / or SRSp configuration based on criteria to ensure accurate and timely measurement of PRS and SRSp in TRP / gNBs within the WTRU. In such cases, the criteria configured in the WTRU by either the LMF or the RAN may be determined as a function of one or more parameters described herein. When supporting DL&UL positioning, the triggering conditions / timing for the WTRU to transmit an on-demand request for PRS and / or SRSp configuration may be performed according to one or more of the following.

[0192] Triggering conditions for transmitting an on-demand request may be based on the exchange of WTRU capability information. For example, the WTRU may transmit an on-demand request for a PRS configuration when it receives a request from the LMF via LPP signaling for WTRU capability information. In another example, the WTRU may transmit an on-demand request for a PRS and / or SRSP to the RAN when it receives a request for capability information from the LMF / RAN. In this case, the WTRU may be configured into an SRSp configuration by the RAN based on the on-demand request transmitted by the WTRU for the PRS configuration.

[0193] Triggering conditions for sending on-demand requests may be based on upper-layer / application triggers. For example, in WTRU-based positioning, WTRU may send on-demand requests to PRS and / or SRSp when it receives a trigger for positioning information or a request for a measurement report from upper layers.

[0194] Triggering conditions for sending an on-demand request may be based on the reception of an SRSp configuration. For example, when the WTRU receives at least one SRSp configuration from the RAN (e.g., in an RRC reconfiguration message), it may send an on-demand request for a PRS configuration to the LMF or RAN (i.e., gNB). The WTRU may send an on-demand request for a PRS after and / or within a predefined time duration from receiving the SRSp configuration.

[0195] Triggering conditions for sending an on-demand request may be based on the evaluation of one or more received SRSp configuration(s). For example, when WTRU determines possible PRS configuration(s) that may not overlap with one or more SRSp configurations provided to WTRU, it may send an on-demand request for a PRS configuration to an LMF or RAN.

[0196] The triggering condition for sending an on-demand request may be based on the activation of an SRSp configuration. For example, when the WTRU receives an activation message (e.g., from MAC CE, DCI) to enable the transmission of an SRSp from the WTRU, it may send an on-demand request for a PRS configuration to the LMF or RAN. The WTRU may send an on-demand request for a PRS only for a subset of SRSp configurations that are determined and provided to the WTRU based on, for example, possibly an SRSp identifier indicated in the activation message.

[0197] Triggering conditions for sending an on-demand request may be based on the reception of the PRS configuration and / or the DL PRS. For example, when the WTRU receives the PRS configuration from auxiliary information (e.g., via a NAS message or via a SIB), it may send an on-demand request to change the PRS to the LMF / RAN and / or an on-demand request to change the SRSp to the RAN. In another example, the WTRU may send an on-demand request for an alternative PRS and / or SRSp based on the measurement of the PRS and measured channel conditions (e.g., the measured RSRP is below a threshold over a given period or across multiple measurement durations / periodisms).

[0198] Triggering conditions for sending on-demand requests may be based on the reception of a request for position information. For example, when the WTRU receives a request for positioning / location information in a NAS message via LPP signaling, it may send an on-demand request for PRS to the LMF / RAN and / or an on-demand request for SRSp to the RAN.

[0199] Triggering conditions for sending an on-demand request may be based on the sending / receiving of a measurement report. For example, when the WTRU completes determining the time difference measurement in the WTRU, it may send an on-demand request for the PRS to the LMF / RAN and / or an on-demand request for the SRSp to the RAN. In another example, for WTRU-based positioning, the WTRU may send an on-demand request for the PRS / SRSp when it receives a measurement report (e.g., consisting of or including RTT, time difference measurements, etc.) from the RAN.

[0200] In one embodiment, the WTRU may include a request for measurement gap reconstruction in an on-demand request associated with the PRS. The WTRU may request one or more different periodicities or durations of the measurement gap. The WTRU may transmit a request for measurement gap reconstruction along with a request for PRS reconstruction. Alternatively, the WTRU may transmit a request for measurement gap reconstruction separately from a request for PRS parameter reconstruction. The WTRU may transmit a request to the network to skip the configuration of the measurement gap to reduce the latency required for positioning. The WTRU may transmit a request to the network to skip the configuration of the measurement gap for the PRS reconfigured by a request from the WTRU. When the WTRU is configured with or is not reconfigured with the measurement gap, the WTRU may decide to use a pre-configured measurement gap or to receive a non-periodic, semi-continuous, or periodic PRS outside the measurement gap. The WTRU may transmit a request to the network to enable the WTRU to receive a configuration for the measurement gap from the network or RAN (e.g., gNB) by the DCI or MAC-CE. The WTRU may transmit a request to the network to enable the WTRU to request the network for the configuration of the measurement gap, PRS, or SRSp by the UCI or MAC-CE. The request by the UCI or MAC-CE may include desired configuration parameters for the transmission of the measurement gap, PRS, or SRSp. The methods described above can reduce the latency required for positioning.

[0201] When transmitting a request for the reconstruction of a measurement gap, WTRU can expect that the timing of the reconstruction of the measurement gap will be aligned with the reconstruction of the PRS parameters, for example, WTRU expects to receive a PRS with reconstructed parameters within the reconstructed measurement gaps.

[0202] In one embodiment, the reconstruction of PRS parameters requires less time than the reconstruction of measurement gaps. In such a case, the WTRU receives PRS outside the measurement gap for a predetermined duration and performs measurements using the received PRS. The WTRU may be configured by a network, during which time the WTRU receives PRS outside the measurement gap. The duration may include at least one of the following: a start time of the duration in terms of a system frame number (SFN), slot number, or symbol number; or a duration in terms of the number of slots or symbols.

[0203] In one method, the reconstruction of the measurement gap requires less time than the reconstruction of the PRS parameters. In such a case, the WTRU does not receive the PRS for every measurement gap. The WTRU may be composed of a duration during which the WTRU does not receive the PRS for every measurement gap. The duration may include at least one of the following: the start time of the duration in terms of the SFN, slot number, or symbol number; or the duration in terms of the number of slots or symbols. In the same embodiment, the WTRU may be composed of the frequency with which the WTRU checks the measurement gap.

[0204] In another embodiment, the WTRU may not receive the PRS until both the PRS and the measurement gap are reconfigured. The WTRU may receive from the network an indication including the timing for the WTRU to receive the PRS having a new configuration during the reconfigured measurement gaps.

[0205] In other embodiments, on-demand non-periodic PRS are utilized. In these embodiments, the WTRU may request the network to transmit non-periodic PRS or semi-continuous PRS. This may be a case during WTRU-based positioning. After analyzing measurement reports, the WTRU may recognize that more PRS need to be transmitted and that periodic PRS may be unnecessary because the WTRU may require short bursts of PRS transmission for improved measurements. In such cases, the WTRU may send a request to the network for non-periodic PRS or semi-continuous PRS. A request for non-periodic PRS may include at least one of the following parameters: the cell ID, TRP ID, or global cell ID to which the non-periodic PRS is to be transmitted; parameters related to the PRS, e.g., the number of symbols, comb patterns; the number of slots containing the non-periodic PRS; the PRS resource ID, the PRS resource set ID, and the PRS ID. Timing of transmission of aperiodic PRS, e.g., number of slots or symbols after an on-demand request has been transmitted; and / or configuration of a measurement gap for aperiodic PRS, e.g., a measurement gap for transmitting the requested PRS.

[0206] A request for a semi-persistent PRS may include at least one of the following parameters: a cell ID, TRP ID, or global cell ID to which the non-periodic PRS is to be transmitted; parameters associated with the PRS, e.g., number of symbols, comb patterns, duration during transmission of the semi-persistent PRS; number of slots containing the semi-persistent PRS; PRS resource ID, PRS resource set ID, PRS ID; timing of transmission of the semi-persistent PRS, e.g., number of slots or symbols after the on-demand request has been transmitted; and / or a measurement gap configuration for the semi-persistent PRS, e.g., a measurement gap for transmitting the requested semi-persistent PRS.

[0207] In another embodiment, a hybrid approach in which on-demand PRS and non-periodic PRS coexist may be utilized. In such an embodiment, the WTRU may determine to use at least one of the following transmission types configured by the network: on-demand PRS; non-periodic PRS triggered by the network; and / or semi-continuous PRS triggered by the network.

[0208] When an aperiodic PRS is configured by the network, the WTRU receives a trigger from the network via DCI signaling when the WTRU anticipates receiving the aperiodic PRS. Similarly, when a semi-continuous PRS is configured by the network, the WTRU may receive a trigger via MAC-CE. In the triggers for DCI and MAC-CE, the WTRU may receive one or more configurations from the network indicating when the aperiodic PRS or semi-continuous PRS may be transmitted by the network. Additionally, in the case of a semi-continuous PRS, the WTRU may receive configurations from the network regarding how long the semi-continuous PRS may be transmitted, its periodicity, and duration. The WTRU may receive configurations from DCI, MAC-CE, or RRC regarding which PRS is configured. When the WTRU receives configurations from DCI, MAC-CE, or RRC, the WTRU may receive an ID number indicating which type of PRS transmission the WTRU is configured to receive.

[0209] In some embodiments, the LMF or WTRU may transmit on-demand requests for aperiodic and / or semi-periodic PRSs. In one example, the WTRU may transmit a request to the network to reconfigure parameters for an aperiodic or semi-periodic PRS. As used throughout this disclosure, "update" or "reconfigure" are used interchangeably. In this disclosure, "semi-periodic" and "semi-periodic" are used interchangeably. A periodic PRS transmission may refer to a transmission of a PRS at a configured periodicity. A periodic PRS transmission may be a transmission of a PRS occurring at a single opportunity in time. A periodic PRS may occupy more than one symbol. The WTRU may receive a DCI containing an indication by the network regarding the timing at which a PRS may be transmitted. The WTRU does not expect to receive a periodic transmission when the WTRU expects to receive a periodic PRS.

[0210] Semi-continuous PRS or semi-periodic PRS transmission may refer to the transmission of a PRS that occurs periodically at a configured periodicity during a predefined time window. In other words, a timer for a semi-continuous PRS transmission may start at the start of the transmission, and once the timer expires after a predefined time has elapsed, the transmission of the semi-continuous PRS is stopped. Alternatively, the semi-continuous PRS may be enabled or disabled by the MAC-CE without a predefined timer.

[0211] Transmission of an aperiodic PRS may be realized by a WTRU or LMF that initiates a request to the network to transmit a PRS at a frequency density and bandwidth configured at one time. The WTRU or LMF may include an indicator that the request corresponds to an aperiodic PRS transmission. The WTRU or LMF may include information regarding when an aperiodic PRS transmission can be triggered.

[0212] Transmission of a semi-continuous PRS may be realized by a WTRU or LMF initiating a request to a network to transmit a PRS at configured frequency densities and bandwidths at configured periodicities. The WTRU or LMF may include an indicator that the request corresponds to the transmission of a semi-continuous PRS. The WTRU or LMF may include information in the request regarding the duration of time during which the semi-continuous PRS is transmitted. The WTRU or LMF may include information regarding when the transmission of a semi-continuous PRS can be enabled.

[0213] In the case of an on-demand request initiated by a WTRU, the WTRU may transmit the request after receiving one or more opportunities for aperiodic or semi-continuous PRSs. The WTRU may request updated bandwidth occupied by a PRS or any of the parameters associated with a PRS described herein, or a combination thereof. For example, the WTRU may transmit a request for additional aperiodic PRSs to an LMF. Additional PRSs may include, for example, different numbers of symbols, comb values, or PRS patterns in the frequency or time domain.

[0214] In other examples, the WTRU may send a request to the LMF for additional semi-persistent PRS with periodicities different from those of the semi-persistent PRS that the WTRU is receiving or is scheduled to receive from the network. The WTRU may send a request to update the parameters of the PRS that the WTRU is scheduled to receive or has already received. For example, the PRS may send a request to the network to update the periodicities of the initial configuration of the semi-persistent or periodic PRS.

[0215] For a request initiated by an LMF, the LMF may include the request in a core network message (e.g., NRPPa) and transmit the message to a gNB or RAN to reconfigure parameters for aperiodic or semi-persistent PRSs. The WTRU may receive notifications regarding parameters reconfigured by a PDCCH or MAC-CE. To minimize the size of the update, the aforementioned notifications may include the parameters that have been updated or reconfigured.

[0216] In the aforementioned request, WTRU can specify a gNB to which a PRS with updated parameters can be transmitted. The network can reconfigure the parameters for the PRS for the specified gNB.

[0217] A request for an aperiodic or semi-continuous PRS may be transmitted for a periodic, semi-continuous, or aperiodic PRS when conditions based on measurements associated with the PRS described herein are satisfied. The following are some examples of conditions when the WTRU transmits a request to update parameters: when the RSRP measured from the received aperiodic or semi-continuous PRS is less than a pre-configured threshold in the WTRU; when the measured TDOA exceeds a pre-configured threshold in the WTRU; and / or when the number of paths observed by the WTRU exceeds a pre-configured threshold in the WTRU.

[0218] When the WTRU sends a request to update parameters, the request may be based on measurements from the WTRU. In the case of WTRU auxiliary positioning, the WTRU may send measurement reports to the LMF. In this case, the LMF may send a request to update parameters for the PRS based on the measurements reported by the WTRU.

[0219] For DL&UL-based positioning methods such as multi-RTT positioning, the WTRU can send on-demand requests for the PRS. The WTRU can be (pre-)configured with rules that associate configurations of the PRS and SRSp. The WTRU sends on-demand requests for the PRS, and the WTRU anticipates a new configuration for the SRSp based on the association rules.

[0220] The WTRU can receive (pre)configuration via higher-layer signaling such as DCI, MAC-CE, or RRC. The WTRU can receive (pre)configuration via LPP / NAS signaling.

[0221] For example, if WTRU is (pre-)configured with an association rule that sets the same periodicity value for PRS and SRSp, and WTRU sends an on-demand request to change the periodicity of PRS transmission to 1ms, then according to the aforementioned association rule, WTRU transmits SRSp with a periodicity of 1ms.

[0222] The WTRU may be (pre-)configured with a timing offset for transmitting an SRSp having new configurations in relation to at least one of the following: when the WTRU transmits an on-demand request for the PRS to the network, and / or when the WTRU receives an acknowledgment from the network indicating receipt of an on-demand request for the reconfiguration of the PRS. The advantage of this scheme is that the WTRU does not need to transmit an on-demand request for the reconfiguration of the SRSp, thereby reducing the resources required to transmit additional on-demand requests.

[0223] In some embodiments, one or more configured acknowledgments may be provided to the WTRU by an LPP / NAS message (e.g., an auxiliary data message provided by the LMF using the LPP protocol). A configured acknowledgment may be associated with one or more PRS configurations. PRS configurations may include periodic, non-periodic, and / or semi-continuous PRS transmit / receive. A configured acknowledgment may be transmitted to the network by the LMF using a core network message (e.g., an NRPPa message).

[0224] In one example, the WTRU may be provided with the priority of measurement reporting data associated with a configured approval. In an LCP procedure, the WTRU may be allowed to multiplex data having a priority higher than the priority of the measurement reporting data. In another approach, the WTRU may be configured as a set of priorities of data to be multiplexed from an approval. For example, the WTRU may be configured to multiplex measurement data that is reported only in the configured approval provided by the LMF.

[0225] In another example, a WTRU can be configured for periodic reporting using one or more configured approvals. A WTRU can report one or more PRS measurement opportunities in one configured approval instance. The number of PRS measurement opportunities can be determined based on the number of opportunities between two configured approval instances.

[0226] In another example, WTRU can filter multiple measurement opportunities between two reporting instances to report a single measurement quantity. Specifically, WTRU can perform a weighted averaging of multiple measurement opportunities to derive a single measurement quantity. Alternatively, WTRU can select the highest and / or lowest measurement value among multiple measurement opportunities to perform reporting. This approach can maintain the same amount of reporting when the number of measurement opportunities varies due to on-demand PRS.

[0227] FIG. 4 is an example (400) of a WTRU bundling multiple measurement opportunities. As illustrated in FIG. 4, initially, the WTRU is configured to report one measurement opportunity per measurement report instance. The WTRU receives a PRS (402), transmits a measurement report (404), receives another PRS (406), and transmits another measurement report (408). As the number of measurement opportunities increases to three, the WTRU may perform an average of the three measurement opportunities so that it can be reported in a single report instance. The WTRU may receive a new PRS timing (410) indicating an increase in measurement opportunities. The WTRU may perform measurements at opportunities (412, 414) and subsequently transmit a measurement report (416). The WTRU may perform measurements at measurement opportunities (418, 420, 422) and transmit a combined measurement report (424).

[0228] In another example, the WTRU may decide to piggyback a positioning measurement report or other measurement reports (e.g., a MIMO measurement report or a CSI report) from a PUCCH transmission. The WTRU may decide whether to piggyback a measurement report based on the amount of data within the report. Specifically, if the amount of data is less than a threshold, the WTRU may piggyback the measurement report. Otherwise, the WTRU may perform the report using PUSCH.

[0229] A potential advantage of these embodiments is that resource usage efficiency can be improved during measurement reporting.

[0230] In other embodiments, differences in the PRS configuration may be reported. For example, after the WTRU sends an on-demand request for the reconfiguration of parameters for the PRS, the WTRU may be (pre-)configured to send measurement reports corresponding to parameters that were not included in the previous configuration. For example, if the WTRU sends an on-demand request to the network for additional beams or resources, the WTRU sends measurement reports corresponding to the requested additional beams or resources. Or, if the WTRU sends an on-demand request to the network to add a TRP to transmit the PRS, the WTRU sends measurement reports corresponding to or associated with the additional TRP.

[0231] The potential benefit of these examples is that WTRU can minimize the use of resources to report measurements. Therefore, the scheme can improve resource utilization in positioning systems.

[0232] The WTRU can be (pre-configured) to report measurements corresponding to new parameters separately. For example, measurement reports may include identification numbers corresponding to requested parameters, such as resource ID, resource set ID, cell ID, or TRP ID. The WTRU can transmit measurement reports and reporting opportunities that differ from the measurement reporting opportunities configured for the original configuration. For example, the WTRU transmits on-demand requests for additional PRSs with different frequency densities to the network. The WTRU is currently configured to report every 1ms. The WTRU transmits measurement reports every 1ms with an offset of 0.5ms from the current measurement reporting opportunities.

[0233] One potential advantage of this embodiment is that the WTRU can flexibly transmit additional measurement reports using available resources, thereby increasing efficiency in resource usage.

[0234] In other embodiments, a measurement gap for the on-demand PRS is utilized. The WTRU can determine which type of MG to request for the on-demand DL-PRS. In one approach, the WTRU may be (pre-)configured by the gNB / MLF with one or any combination of the following MG types: discarding an existing configured MG and requesting a new MG configuration; maintaining an existing configured MG and adding a new MG configuration.

[0235] For example, the WTRU may be composed of a list of MG configurations. The list may include indices where certain indices correspond to the MG configurations (e.g., offset, MG length, periodicity, type of MG (e.g., non-periodic, periodic, semi-continuous)). For example, once the WTRU determines a new MG configuration, the WTRU may transmit the list to the gNB / LMF via a UCI / MAC-CE / RRC / LPP message to request configurations of MGs from the list. The WTRU may receive a list containing multiple MG configurations from the gNB / LMF, for example, as an acknowledgment to a request from the WTRU. Alternatively, the WTRU may receive a list from the gNB / LMF regarding requests related to on-demand PRS from the WTRU, for example. The WTRU may determine from the list that the WTRU receives a PRS that may be requested by the WTRU or configured by the LMF / gNB during the configured MGs.

[0236] In the present disclosure, "on-demand PRS", "requested PRS", "updated PRS", "PRS update", "PRS request", "WTRU initiated PRS", "WTRU triggered PRS", "LMF initiated PRS", "LMF triggered PRS", and "PRS" may be used interchangeably.

[0237] WTRU may determine which MG type to request for receiving an on-demand DL-PRS based on one or any combination thereof: the type of the on-demand DL-PRS; the duration of the on-demand DL-PRS; the periodicity of the configured MG configuration and the periodicity of the on-demand DL-PRS; and / or the maximum and / or minimum time gap between the configured MG and the on-demand DL-PRS in a single period. The type of the on-demand DL-PRS may be periodic, semi-continuous, or non-periodic. For example, WTRU may always request to maintain the existing configured MG for the on-demand DL-PRS and add a new MG configuration. The duration of the on-demand DL-PRS. For example, WTRU may request the reception of a DL-PRS for a specific duration of time. The duration of time may be indicated by WTRU as a number of slots, symbols, or frames. The WTRU may send an indication to the LMF having the start time and / or end time of the requested DL-PRS. The WTRU may send the request to the gNB via UCI / MAC-CE / RRC or to the LMF via LPP, for example. With respect to the periodicity of the configured MG and the periodicity of the on-demand DL-PRS, for example, if the periodicity of the configured MG differs from the periodicity of the on-demand DL-PRS, the WTRU may request to retain the existing configured MG and add a new MG configuration.

[0238] In one cycle, with respect to the maximum and / or minimum time gap between the configured MG and the on-demand DL-PRS, specifically, if the maximum time gap between the configured MG and the on-demand DL-PRS is smaller than the threshold, the WTRU may discard the existing configured MG and request a new MG configuration. Otherwise, if the maximum time gap between the configured MG and the on-demand DL-PRS is larger than the threshold, the WTRU may retain the existing configured MG and request the addition of a new MG configuration. The threshold may be fixed or configured by the gNB / LMF.

[0239] For example, if the periodicity of the configured MG is the same as the periodicity of the on-demand DL-PRS, the WTRU can determine which MG type to request based on the difference between the offset difference between the configured MG and the on-demand DL-PRS. If the offset difference is smaller than a threshold, the WTRU can discard the existing configured MG and request a new MG configuration. Otherwise, the WTRU can retain the existing configured MG and add a new MG configuration.

[0240] WTRU can determine the MG length (MGL) for each configured MG period when the WTRU is (pre-configured) with multiple MGs. WTRU can first determine the periodicity of the combined configured MGs. The periodicity of the combined MGs may be the minimum periodicity of the configured MGs. MGL may be the time from the first MG to the last MG in a single period. WTRU can transmit information related to the combined MGs to the gNB. For example, WTRU can transmit indices associated with the combined MGs to the gNB and include an indication that the MGs corresponding to the indices are combined to extend the MGL.

[0241] In one method, the WTRU can determine whether to stop monitoring the PDCCH during the duration between two configured MGs based on the time gap between two configured MGs. Specifically, the WTRU can expect that there will be no PDCCH targets for the WTRU if the time gap between two configured MGs is smaller than a threshold. Subsequently, the WTRU can process the DL-PRS during the time between two MGs, and it can stop monitoring the PDCCH during such duration. The time gap threshold can be fixed or configured by the gNB / LMF.

[0242] FIG. 5 is an example of a WTRU having two configured MGs that determine whether to stop monitoring the PDCCH. As illustrated in FIG. 5, there are two scenarios, namely Scenario 1 (500) and Scenario 2 (520). In each scenario, the WTRU may be composed of two MGs having the same periodicity in yellow and green colors.

[0243] In Scenario 1 (500), the first MG (502) and the second MG (504) bookend the PDCCH monitoring period (506). The WTRU may be configured with a threshold (508) for monitoring the PDCCH. Because the threshold (508) is temporally shorter than the gap period (510) between the MG (502) and the MG (504), the WTRU can monitor the PDCCH (506). The MG (512) and the MG (514) may be on resources that occur periodically. In this scenario (500), the WTRU may need to monitor the PDCCH (506) during the time between two MGs (502, 504) because the time gap (510) between the two MGs (502, 504) is greater than the time gap threshold (508).

[0244] In scenario 2 (520), MG (522) and MG (524) can bookend PDCCH (526). In this scenario (520), the gap period (530) may be smaller than the threshold (528), and thus WTRU may stop monitoring PDCCH (526) because the time gap between the two configured MGs (522, 524) is smaller than the time gap threshold (528).

[0245] In other embodiments, WTRU may determine which MG pattern to request. The MG pattern may include one or any combination of the following: whether the pattern is periodic, semi-continuous, or non-periodic; offset; MG length; periodicity.

[0246] WTRU may determine which MG pattern to request based on one or any combination of the following: configuration of an on-demand DL-PRS; existing configured MG; whether a certain type of traffic (e.g., URLLC) is configured or supported; and / or whether a certain procedure / event is being executed / occurring.

[0247] In one example, the WTRU can be configured with a mapping between a DL-PRS configuration and a single MG configuration (e.g., by gNB / LMF). Subsequently, the WTRU can determine which MG configuration to request based on the on-demand DL-PRS configuration and the configured mapping.

[0248] In one example, when URLLC is configured, WTRU may be prohibited from requesting MG configurations. In another example, when URLLC traffic is configured, WTRU may be restricted to requesting a subset of MG configurations. Specifically, when URLLC traffic is configured, WTRU may be prohibited from requesting MG configurations with high MGL and / or low periodicity.

[0249] WTRU may be prohibited from requesting MG configuration or restricted to requesting a subset of MG configuration if one of the following procedures / events is executing / triggered: handover procedures, recovery procedures (e.g., beam recovery procedures); RLF events.

[0250] In other embodiments, the WTRU determines whether to request an MG for a DL-PRS reception. In one example, the WTRU may determine whether to request an MG for a DL-PRS reception based on one or any combination of the following: the configured bandwidth of the DL-PRS; the pattern of the on-demand DL-PRS; the report configuration; and / or the QoS of the positioning service.

[0251] Using the configured bandwidth of the DL-PRS, for example, the WTRU may decide to perform measurement grant-less (MG-less) DL-PRS reception if the configured bandwidth of the DL-PRS is within the WTRU's active BWP. Otherwise, the WTRU may request an MG for the DL-PRS reception.

[0252] Using the pattern of the on-demand DL-PRS, for example, the WTRU can perform MGless DL-PRS reception for non-periodic on-demand DL-PRS or semi-continuous on-demand DL-PRS, and the WTRU can request MG for the periodic on-demand DL-PRS.

[0253] Alternatively, WTRU can request an MG of the same type compared to the type of on-demand PRS. For example, WTRU can request a non-periodic MG for a non-periodic on-demand PRS. In another example, WTRU can request a semi-periodic MG for a semi-periodic PRS. Finally, WTRU can request a periodic MG for a periodic PRS.

[0254] The semi-persistent MG can be enabled or disabled by the WTRU / gNB via MAC-CE. Alternatively, the semi-persistent MG can be disabled once the timer expires. The timer can start when the semi-persistent MG is enabled via MAC-CE. In another example, the semi-persistent MG can start and end at specified times (e.g., slot number, symbol number, frame number, SFN, timestamp).

[0255] In one example, the WTRU may perform MGless DL-PRS reception for non-periodic reporting, and the WTRU may request an MG for periodic reporting. In another example, the WTRU may perform MGless DL-PRS reception if the periodicity of the measurement report is greater than a threshold; otherwise, the WTRU may request an MG for DL-PRS reception. The threshold may be configured by LMF / gNB.

[0256] Using the QoS of a positioning service, for example, a WTRU can perform MGless DL-PRS reception for one positioning service (e.g., a positioning service requiring low position accuracy and / or redundant position updates / measurement reports), and it can perform MG-based DL-PRS reception for another positioning service (e.g., a positioning service requiring high position accuracy and / or frequent position updates / measurement reports).

[0257] In other embodiments, the WTRU performs DL-PRS reception from configured periodic DL-PRS transmissions. In one approach, the WTRU may be configured for periodic on-demand DL-PRS, where the gNB / TRP may transmit the DL-PRS periodically. However, the WTRU may perform one or any combination of DL-PRS reception types: non-periodic reception of DL-PRS from the TRPs of the serving gNB; non-periodic reception of DL-PRS from the TRPs of neighboring gNBs; semi-continuous reception of DL-PRS from the TRPs of the serving gNB; semi-continuous reception of DL-PRS from the TRPs of neighboring gNBs; periodic reception of DL-PRS from the TRPs of the serving gNB; periodic reception of DL-PRS from the TRPs of neighboring gNBs.

[0258] As shown in FIGS. 6, 7, and 8, the WTRU can perform non-periodic reception, semi-continuous, and periodic DL-PRS reception, respectively.

[0259] FIG. 6 is an example of a WTRU performing aperiodic reception of periodic PRS (600). In the embodiment illustrated in FIG. 6, a PRS timeline (602) and an MG / measurement occasion (MO) schedule (604) may be configured. PRS (606 to 618) may be transmitted periodically. The WTRU may receive a DCI (620) indicating the scheduling of the MG / MO and indicating that the WTRU is performing aperiodic reception. The WTRU may perform PRS reception (622) on the resources indicated by the DCI (620).

[0260] FIG. 7 is an example of a WTRU performing semi-continuous reception of periodic PRS (700). In the embodiment illustrated in FIG. 7, a PRS timeline (702) and an MG / MO schedule (704) may be configured. PRS (706 to 718) may be transmitted periodically. The WTRU may receive a MAC CE (720) indicating the activation of the MG / MO (720) for PRS measurement, and the WTRU may subsequently receive PRS at 724 to 730. The WTRU may receive a MAC CE (722) deactivating the MG / MO.

[0261] FIG. 8 is an example of a WTRU performing periodic PRS measurements (800) at different frequency measurement opportunities. In the embodiment illustrated in FIG. 8, a PRS timeline (802) and an MG / MO schedule (804) may be configured. PRS (806 to 818) may be transmitted periodically. The WTRU may receive an indication (820) via RRC, MAC CE, or DCI indicating the activation of the MG / MO (820) with a periodicity for PRS measurements different from the periodicity of the PRS transmission. The WTRU may subsequently receive PRS at 822 to 826 according to the periodicity of reception.

[0262] In other embodiments, the WTRU may determine which DL-PS reception behavior to perform. In one type of DL-PRS reception, the WTRU may further determine one or any combination of the following parameters: an offset of the DL-PRS reception; periodicity of the DL-PRS reception; and the number of DL-PRS receptions for non-periodic DL-PRS reception.

[0263] WTRU may determine the DL-PRS reception type, associated parameters, and / or the corresponding MG configuration based on one or any combination of the following: indication from the upper layer or network; QoS of the positioning service; measurement results made for the configured PRS configuration; measurement reporting configuration; and / or configured on-demand DL-PRS patterns of serving gNBs and / or neighboring gNBs.

[0264] For example, using indications from a higher layer or network (e.g., LMF), the network may indicate which types of DL-PRS measurements the WTRU may need to perform. Using the QoS of the positioning service, for example, the WTRU may perform periodic DL-PRS receptions on every configured on-demand DL-PRS transmission if the positioning service may require a high accuracy level and frequent positioning reports. Alternatively, the WTRU may perform periodic DL-PRS receptions, where each DL-PRS reception is performed after a predetermined number of DL-PRS transmissions for relaxed positioning accuracy requirements and less frequent positioning measurement reporting. Using measurement results made for a configured PRS configuration, for example, the WTRU may perform non-periodic DL-PRS receptions based on measurement results made based on the configured PRS configuration. The WTRU can trigger an on-demand DL-PRS measurement when one or more configured DL-PRS are deprioritized. The WTRU can also trigger a non-periodic on-demand DL-PRS when RSRP measurements in one or more configured DL-PRS are less than a threshold or when an NLOS condition is detected in one or more configured TRPs. The RSRP threshold can be configured by gNB / LMF. Using measurement reporting configurations, for example, the WTRU can perform non-periodic DL-PRS reception for a non-periodic measurement reporting configuration. The WTRU can perform periodic DL-PRS reception for a periodic measurement reporting configuration. Using configured on-demand DL-PRS patterns of serving gNBs and / or neighboring gNBs, for example, WTRU may request an MG for each reception of a neighboring gNB, and WTRU may not request an MG for reception of a serving gNB if the configured DL-PRS is within WTRU's active BWP.

[0265] In other embodiments, reporting of measurements associated with non-order and / or on-demand PRS configurations is described. In some instances, the WTRU transmits to the network measurement reports consisting of or composed of measurements made for PRS resources associated with one or more non-order PRS configurations and / or on-demand PRS configurations. "Non-order PRS" may be PRS resources or resource sets configured by the network for the WTRU prior to the WTRU or the network (e.g., LMF) initiating a request for an on-demand PRS resource or resource set, or a change of parameters for an on-demand PRS resource(s). The requested parameters may be any of the parameters mentioned herein. The PRS resources for which the WTRU can perform measurements may include one or more of time / frequency resources, resource sets, beams and / or TRPs / gNBs / cells. The PRS resources configured in the WTRU may be associated with non-order PRS configurations and / or on-demand PRS configurations. PRS resources associated with non-order PR configurations and / or order PRS configurations may be identified and / or assigned the same or different identifiers / labels / indexes. For example, a PRS resource may be identified as ID '1a' when associated with a non-order PRS having ID 'a', and a PRS resource may be identified as ID '1b' when associated with an order PRS having ID 'b'. A WTRU may, for example, use a non-order PRS configuration to perform a first set of measurements and then use an order PRS configuration to perform a second set of measurements. In this case, the WTRU may use the order PRS configuration to perform the second set of measurements, for example, at the triggering of an order PRS procedure (e.g., an order request initiated by WTRU or LMF).Possibly, a second set of measurements made on on-demand PRS resources may be intended to improve, for example, the accuracy of positioning information.

[0266] The first and second sets of measurements may be interchangeable, that is, the WTRU may perform the first set of measurements for the on-demand PRS and the second set of measurements for the non-on-demand PRS. The WTRU may measure the on-demand PRS and the non-on-demand PRS in succession. For example, the non-on-demand PRS may be configured to be transmitted from the TRP every 10 ms, while the on-demand PRS may be transmitted from the TRP every 3 ms. The WTRU may, for example, measure the non-on-demand PRS every 10 ms while measuring the on-demand PRS every 3 ms. For example, the order of the measurements (e.g., whether to perform the first set of measurements or the second set of measurements initially) may be configured by the network in the WTRU (by providing a configuration for the order of measurements to be performed) or may be determined autonomously by the WTRU based on certain rules configured by the network. The rules may indicate, for example, performing a first set of measurements when a first condition is satisfied (e.g., the RSRP of the PRS is below a threshold), and then performing a second set of measurements when a second condition is satisfied (e.g., the RSRP of the PRS is above a threshold).

[0267] The types of non-order PRS configurations that can be configured in the WTRU may include periodic, non-periodic, and / or semi-continuous PRS configurations. Different types of non-order PRS configurations may include associated parameters (e.g., periodicity, time / frequency resources, measurement duration, beams, TRP / gNB / cell, associated IDs), which may also be configured in the WTRU together with the non-order PRS configurations, for example. The WTRU may be composed of one or more on-demand PRS configurations, possibly used when an on-demand PRS procedure is triggered. On-demand PRS configurations may also be composed of different types, including periodic, non-periodic, and / or semi-continuous on-demand PRS configurations. Possibly, different types of custom PRS configurations configured in WTRU may also be associated with parameters that are the same or different from the parameters of non-custom PRS configurations (e.g., periodicity, beams, TRPs / gNBs / cells).

[0268] The WTRU may use a measurement report configuration to transmit measurement reports to the network. The measurement report configuration may be associated, for example, with parameters applicable to the type of PRS configuration. In this case, the measurement report configuration may be explicitly configured in the WTRU or implicitly determined by the WTRU based on the PRS configuration configured in the WTRU. In an example where the WTRU may be configured with a periodic non-order / order PRS configuration, the measurement report configuration may indicate that the WTRU transmits measurement reports according to similar parameters associated with the type of PRS configuration. When configured with a periodic non-order / order PRS configuration, the WTRU may transmit measurement reports to the network, possibly periodically, with a predetermined periodicity and / or a specific offset that may align with periodic PRS measurements. In another example where the WTRU can be configured with a non-periodic non-on-demand / on-demand PRS configuration, the WTRU can transmit a measurement report in at least a single shot transmission, possibly aligned with a non-periodic PRS measurement.

[0269] The reporting behavior for WTRU auxiliary positioning is described herein. When WTRU performs measurements on PRS resources, it may transmit measurement reports to a network in at least one combination of the following.

[0270] Measurements made for PRS resources associated with non-on-demand PRS configuration(s) may be reported. For example, the WTRU may send a measurement report consisting of measurements made for non-on-demand PRS resources before, during, and after sending an on-demand request. The WTRU may send a measurement report including measurements made for non-on-demand PRS resources, for example, after receiving a trigger to start taking measurements for the on-demand PRS configuration and / or on-demand PRS resources.

[0271] Measurements made for PRS resources associated with on-demand PRS configuration(s) may be reported. For example, after receiving an on-demand PRS configuration and / or making measurements for on-demand PRS resources, the WTRU may transmit a measurement report consisting of or composed of measurements made for on-demand PRS resources. In one example, when the WTRU makes measurements for on-demand PRS resources triggered by an on-demand procedure and / or when the WTRU makes measurements for on-demand PRS resources, it may transmit at least the measurements made for on-demand PRS resources in the measurement report, possibly without including measurements made for non-on-demand PRS resources. The WTRU may receive reporting configurations from the network, such as reporting periodicities, the number of reports, and / or reporting durations for on-demand PRS resource(s).

[0272] Measurements made for PRS resources associated with both non-on-demand and on-demand PRS configuration(s) may be reported. For example, after receiving an on-demand PRS configuration and / or making measurements for on-demand PRS resources, the WTRU may transmit a measurement report consisting of or composed of measurements made for both non-on-demand PRS and on-demand PRS resources. In one example, when transmitting measurement reports, the WTRU may label and / or indicate the measurements corresponding to the non-on-demand and on-demand PRS configurations (e.g., the WTRU includes identifiers / indexes associated with the PRS configurations). In another example, the WTRU may indicate the timing information associated with making measurements using the non-on-demand PRS / on-demand PRS configurations in the measurement report transmitted over the network. For example, when using a non-on-demand PRS configuration and / or an on-demand PRS configuration, the WTRU may report timing information including at least one of a start time (e.g., start slot number), a measurement duration (e.g., number of slots), and a stop time (e.g., stop slot number). In another example, the WTRU may perform measurements using both on-demand PRS and non-on-demand PRS and report the measurements. For example, the WTRU may send a request to the LMF to transmit a PRS from a new set of TRP(s) (e.g., one or more TRPs within a serving cell and / or neighboring cells). In response to the request, the LMF may indicate which TRP may be used as a reference TRP for the RSTD measurements. Using the reference TRP, the WTRU may perform measurements for the RSTDs on the received on-demand PRS resource(s). WTRU can transmit measurement reports containing RSTDs corresponding to on-demand PRS resource(s) to LMF. Alternatively, LMF can indicate to WTRU that reference TRPs for non-on-demand PRSs should be used.In such cases, the WTRU measures the RSTDs between the on-demand PRS resource(s) and the PRS resource transmitted from the reference TRP. The WTRU can combine the RSTD measurements made using the on-demand PRS resource(s) and the non-on-demand PRS resource(s).

[0273] In another example where an on-demand procedure to improve positioning accuracy is triggered, the WTRU may, when transmitting measurement reports, replace at least some of a first set of measurements (e.g., for non-on-demand PRS resources) with a second set of measurements (e.g., for on-demand PRS resources). In another example, when transmitting measurement reports, the WTRU may combine the first set of measurements (e.g., for non-on-demand PRS resources) and the second set of measurements (e.g., for on-demand PRS resources) with a specific operation (e.g., summing, averaging).

[0274] When performing measurements on PRS resources associated with one or more non-on-demand / on-demand PRS configurations, the WTRU may transmit the entire set of measurements (i.e., all configured PRS resources) and / or a subset of measurements (i.e., a subset of PRS resources) in the measurement reports. The subset of measurements may include, for example, measurements performed on PRS resources sufficient to satisfy a specified positioning accuracy requirement. In this case, the WTRU may include in the measurement report measurements of at least PRS resources configured by a network (e.g., LMF, gNB), where the RSRP is above a threshold and / or the TDoA / AoA variation is below a threshold. For example, measurements performed on PRS resources (e.g., resource sets / beams / TRPs / gNBs) that may not be sufficient to satisfy a specified positioning accuracy requirement. In one example, WTRU may include in its measurement report measurements of at least PRS resources indicating RSRP below a threshold and / or TDoA / AoA variation above a threshold, configured by a network (e.g., LMF, gNB).

[0275] When transmitting a measurement report, WTRU can identify and / or label measurements corresponding to the entire set and / or subsets by ID / index. WTRU can also identify and label PRS resources included in the subsets by ID / index.

[0276] WTRU can determine whether to transmit a combination of both a full set of measurements, a partial set of measurements, and / or sets of measurements corresponding to non-on-demand / on-demand PRS configurations in a measurement report based on one or more of PRS configurations, reporting rules, detection of changes in measurements, and / or tracking of report counts.

[0277] For example, WTRU can determine the set of measurements to be included in a measurement report based on the applied PRS configuration. WTRU can transmit the entire set, for example, when measurements are taken for PRS resources associated with a non-on-demand PRS configuration. Similarly, WTRU can transmit a partial set corresponding to PRS resources associated with a PRS configuration, for example.

[0278] Reporting rules can be configured by the network. For example, the WTRU can transmit the entire set of measurements in the first reporting instance and a subset of measurements in the second / subsequent reporting instance(s). The WTRU can select the measurements to be reported from the subset for the second reporting instance(s) based on a margin of change in the measurements (e.g., by a predetermined threshold).

[0279] WTRU may transmit the entire set of measurements in the second reporting instance when the entire set is transmitted in the first reporting instance when the measurements made for at least one of the PRS resources increase or decrease by a predetermined threshold. Likewise, WTRU may transmit a partial set of measurements in the second reporting instance when the entire set is transmitted in the first reporting instance, for example, when the measurements made for the PRS resources are within a predetermined upper / lower threshold margin.

[0280] WTRU can transmit the full set after counting N report instances, while WTRU can transmit a subset in the measurement report.

[0281] In another embodiment, reporting behavior for WTRU-based positioning is defined. In WTRU-based positioning methods, the WTRU performs measurements on PRS resources and determines its position without transmitting measurement reports to a network (e.g., to an LMF). For WTRU-based positioning, when performing measurements on PRS resources, the WTRU may transmit its position information (e.g., latitude, longitude, altitude, and / or uncertainty shape) to a network, comprising at least one of the following: measurements made on PRS resources associated with non-order PRS configuration(s), measurements made on PRS resources associated with order PRS configuration(s), and / or measurements made on PRS resources associated with both non-order and order PRS configuration(s).

[0282] WTRU may transmit location information consisting of location information determined, possibly using measurements made on non-on-demand PRS resources, before, during, and after transmitting an on-demand request. WTRU may transmit location information, for example, after receiving a trigger to start performing on-demand PRS configurations and / or measurements on on-demand PRS resources.

[0283] After receiving an on-demand PRS configuration and / or performing measurements on on-demand PRS resources, the WTRU may transmit location information determined, possibly based on measurements performed on on-demand PRS resources. In one example, when the WTRU is triggered by an on-demand procedure and / or performs measurements on on-demand PRS resources, the WTRU may transmit location information using at least measurements performed on on-demand PRS resources, possibly without including measurements performed on non-on-demand PRS resources. The WTRU may indicate in a report that the WTRU's location information is based on measurements performed on on-demand PRS resources.

[0284] WTRU may determine to include first and / or second type location information estimated using measurements made on first or second type PRS resources based on measurement conditions. An example of first type location information may be location information derived based on measurements made on non-on-demand PRS resources (i.e., first type PRS resources). An example of second type location information may be location information derived based on measurements made on on-demand PRS resources (i.e., second type PRS resources).

[0285] For example, after receiving an on-demand PRS configuration and / or performing measurements on on-demand PRS resources, the WTRU may transmit location information using measurements made on both non-on-demand PRS and on-demand PRS resources. In one example, the WTRU may label and / or indicate location information corresponding to the non-on-demand and on-demand PRS configurations, for example, the WTRU may include identifiers / indexes associated with the PRS configurations, and the WTRU may indicate that location information is generated based on both measurements made on on-demand PRS resources and non-on-demand PRS resources, and / or the WTRU may indicate that, when transmitting location information, location information is generated based on measurements made only on non-on-demand PRS resources or only on on-demand PRS resources. The WTRU may receive both on-demand PRS and non-on-demand PRS, but the WTRU may decide to use selected resources of PRS (some on-demand PRS resources and non-on-demand PRS) due to poor RSRP or long delay in receiving one of the PRS types (e.g., on-demand PRS or non-on-demand PRS) or some of the PRS resources. The WTRU may choose to use measurements for PRS resources under at least one of the following conditions: if the RSRP is above a threshold configured by the network (e.g., LMF) or if the delay in reception is below a threshold configured by the network (e.g., LMF).

[0286] Indications of the types or IDs of PRS resources used in measurements can help the network (e.g., LMF) optimize PRS transmission.

[0287] In another embodiment, the WTRU may include multiple location information, one derived / estimated using measurements made for non-on-demand PRS and the other derived / estimated using measurements made for on-demand PRS. The WTRU may associate two location information with on-demand PRS and non-on-demand PRS. The WTRU may decide to transmit two location information in a single report based on at least one of the following conditions: the RSRP(s) of the on-demand and on-demand PRS resources are above a threshold configured by the network (e.g., LMF), and / or the delay in reception of the on-demand PRS and non-on-demand PRS resource(s) is below a threshold configured by the network (e.g., LMF).

[0288] In another embodiment, the WTRU may include only one of location information derived / estimated using measurements made for non-order PRS or on-demand PRS. The WTRU may associate location information with on-demand PRS and non-order PRS. The WTRU may decide to transmit one location information in a report based on at least one of the following conditions: the RSRP(s) of resources for one of the PRS types (e.g., non-order PRS or on-demand PRS) are below a threshold configured by the network (e.g., LMF), and / or the delay in one of the PRS types (e.g., non-order PRS or on-demand PRS) is above a threshold configured by the network (e.g., LMF).

[0289] In one embodiment, an on-demand PRS request may be sent by the WTRU before reaching a target number of reports. The WTRU may rely on an indication to send an on-demand PRS request before it completes a configured number of measurements and / or generates a configured number of measurement reports.

[0290] The initial configuration may be as follows. In WTRU auxiliary positioning, the WTRU may be configured by the network (e.g., LMF or gNB) to have the network transmit reports of a target number of measurements, where the reports may be transmitted periodically to the network by the WTRU. Additionally, the WTRU may receive a configuration for the periodicity of the reports from the network.

[0291] Before reaching the limit, an explicit indication to transmit an on-demand PRS request may be used. The WTRU may explicitly receive an indication from the network. Before the WTRU transmits its first measurement report, the WTRU may receive an indication from the network (e.g., LMF or gNB) to transmit an on-demand request for PRS configuration at one of the following opportunities: before it has completed transmitting the configured number of measurement reports; or after it has completed transmitting the configured number of measurement reports. The indication from the network may be included in an LPP message or in an RRC, MAC-CE, or DCI.

[0292] If the number of measurement reports is configured to be infinite, that is, if the WTRU can continue to transmit reports until positioning is interrupted or terminated by the network (e.g., when the LPP session is released), the WTRU may determine that an on-demand request for PRS reconfiguration can be transmitted at any time. Positioning may be interrupted or terminated by an LPP message transmitted by the network.

[0293] If the WTRU does not receive a signal, the WTRU may perform the following behaviors / actions. If the WTRU does not receive a signal from the network and the number of reports configured to be transmitted to the network is a finite number (e.g., 64), the WTRU may transmit an on-demand request for PRS configuration after transmitting the last report among the configured number of measurement reports.

[0294] Once the WTRU sends an on-demand request for PRS reconfiguration and the request is accepted by the network (e.g., acknowledged by a message sent from the network), the WTRU may decide that the counter for the number of reports is reset (e.g., reset to 0) so that the WTRU sends measurement reports until the target number of reports (e.g., the number of reports configured by the WTRU before the WTRU sends the on-demand PRS request) reaches the reconfigured PRS parameters. Alternatively, the WTRU may decide that the WTRU maintains the counter and continues to increment the counter without resetting it to 0.

[0295] Whether the WTRU resets the counter or continues to increment the counter may depend on at least one of the following conditions: the WTRU receives, after an on-demand request for PRS reconfiguration is accepted, an explicit indication to reset the counter or continue to increment the counter from the network (e.g., LMF or gNB) via an LPP message, RRC, MAC-CE, or DCI; the WTRU transmits an indication to the network to reset the counter or continue to increment the counter; the WTRU receives an indication from the network commanding the WTRU to reset the counter or continue to increment the counter, depending on the contents of the on-demand PRS.

[0296] If an on-demand request from WTRU includes at least one of the following parameters, WTRU may decide to continuously increment the counter based on the number of TRPs transmitted by PRS or the number of PRS resources per set of PRS resources. Including only the number of TRPs means that WTRU requests a change from the transmitting source, so the measurements may not change abruptly, justifying the continuous incrementing of the counter.

[0297] If an on-demand request includes at least one of the following parameters, the WTRU may reset counters for measurement reports: parameters related to the PRS, e.g., periodicity, comb size, number of symbols, QCL information, bandwidth, repetition factor, or any parameters related to the PRS; resource ID or resource set ID; beam directions; on / off indicator for the PRS; number of frequency layers or frequency layer indicator; muting pattern.

[0298] WTRU may be composed of conditions for transmitting an on-demand PRS request. Based on measurements, WTRU may transmit an on-demand request for PRS reconstruction. Conditions for transmitting an on-demand request for PRS reconstruction may be based on any of the conditions of this specification. For example, WTRU may transmit an on-demand request for PRS reconstruction if at least one of the following conditions is satisfied: the RSRP of the received PRS is below a (pre)configured threshold; the range or standard deviation in the RSRP of the received PRS is above a (pre)configured threshold; the range or standard deviation in the AoA of the received PRS is above a (pre)configured threshold; the range or standard deviation in the TDOA or ToA of the received PRS is above a (pre)configured threshold; for WTRU-based positioning, the standard deviation or range of the position estimate is above a (pre)configured threshold.

[0299] FIG. 9 is a flowchart (900) of a procedure for transmitting an on-demand PRS reconfiguration request. The WTRU may receive from the LMF an indication to transmit M measurement reports transmitted every T seconds (902). The WTRU may also receive from the LMF an indication to transmit an on-demand request, if necessary, before the number of transmitted measurement reports reaches M (904). The WTRU receives PRS configurations from the LMF. The WTRU receives the PRS (906) and may perform measurements (908). The WTRU may transmit a measurement report at the configured periodicity (910) and increment the measurement report counter (912). When the counter reaches M (914), the WTRU may terminate the positioning (916).

[0300] Otherwise, the WTRU can check whether one of the conditions for sending an on-demand PRS reconfiguration request is satisfied (918). If it is not satisfied, the WTRU can continue to receive PRS (906). If the condition for sending an on-demand PRS reconfiguration is satisfied, the WTRU can send an on-demand PRS reconfiguration request (e.g., requesting more frequent transmission of PRS) to the LMF (920). If the WTRU receives an acknowledgment for the on-demand PRS reconfiguration (922), the WTRU can decide whether to reset the measurement counter based on the content of the on-demand PRS reconfiguration request (924). The WTRU can continue to receive PRS (906).

[0301] If the WTRU consists of a large number of reports, the WTRU or network may need to wait until the configured number of measurement reports are transmitted, which can increase latency to achieve accurate positioning. Such indications provide the WTRU flexibility to change the PRS configuration and reduce latency to achieve accurate positioning.

[0302] The association between the start / end times for PRS transmission and the number of reports can be configured. In one embodiment, the WTRU may transmit an on-demand PRS request including the start and end times of the PRS transmission. The PRS transmission having the requested start and end times may be a new set of PRS-related parameters such as periodicity, comb size, and the number of symbols. The start and end times may be indicated, for example, by a system frame number, slot number, or symbol number. The start and end times may be indicated relatively. For example, the start time may be defined in relation to the time when the on-demand PRS request is transmitted. For example, the start time may be defined by the number of frames, slots, or symbols from the timing when the on-demand PRS request is transmitted. Similarly, the end time may be defined in relation to the start time or the time when the on-demand PRS request is transmitted. Alternatively, the WTRU may include the start time and duration for which the on-demand PRS is transmitted from the network.

[0303] The WTRU can determine the number of measurement reports based on the start / end times of the on-demand PRS transmission. Before the WTRU transmits an on-demand PRS reconfiguration request, the WTRU can be configured with the number of measurement reports to transmit and the periodicity at which the WTRU transmits the measurement reports to the network.

[0304] When the WTRU transmits an on-demand PRS request indicating the start / end time of the on-demand PRS transmission (or the start and duration of the on-demand PRS transmission), the WTRU can determine that the same number of measurement reports and periodicity are associated with the on-demand PRS transmission.

[0305] For example, the initial configuration of the target number of measurement reports and the periodicity of PRS transmission can be 10 and 1 second, respectively. If the on-demand PRS duration is 20 seconds with a periodicity of 1 second for PRS transmission, the WTRU can transmit up to 20 reports to the network. However, since the initial target number of reports is 10, the WTRU decides to transmit only up to 10 reports and stop positioning after transmitting the last report.

[0306] Alternatively, the WTRU may determine that it can determine a new target number of measurement reports based on the initial configuration of the periodicity of the report transmission and the on-demand PRS configuration (e.g., the periodicity of the on-demand PRS transmission). For example, the target number of measurement reports and the initial configuration of the periodicity of the PRS transmission may be 10 and 1 second, respectively. If the on-demand PRS duration is 8 seconds at a periodicity of 1 second for the PRS transmission, the WTRU may transmit a maximum of 8 reports to the network. Since the number of possible reports to transmit is less than the initial target number of reports, i.e., 10, the WTRU determines that the maximum number of reports to transmit is 8.

[0307] WTRU can decide to select the smaller value between the number of reports that can be generated for on-demand PRS transmission and the initial number of reports to be transmitted.

[0308] Alternatively, the WTRU may receive an indication from the network (e.g., LMF or gNB) to adjust the number of measurement reports based on the duration of the on-demand PRS transmission. Using the example described above, the initial configuration of the target number of measurement reports and the periodicity of the PRS transmission may be 10 and 1 second, respectively. If the on-demand PRS duration is 20 seconds with a periodicity of 1 second for the PRS transmission, the WTRU may transmit up to 20 reports to the network. Thus, the WTRU decides to transmit 20 reports instead of the 10 measurement reports originally configured to be transmitted.

[0309] Alternatively, the WTRU can receive from the network an indication of periodicity associated with the new number of measurement reports and the reconfigured PRS transmission.

[0310] WTRU can determine the number of reports to be transmitted based on the start / end time or start and duration of the on-demand PRS, thereby saving overhead from the network for signaling the number of reports that WTRU needs to transmit to the on-demand PRS.

[0311] In one embodiment, the WTRU may be configured by a network (e.g., LMF or gNB) to perform measurements based on a configured number of samples of the received PRS. The WTRU may transmit requests for different numbers of samples to the network based on the measurements made by the WTRU. For example, the WTRU may perform measurements on M instances of a set of DL PRS resources on the PRS resources. The value of M may be an integer greater than 1. The number of samples may be correlated with latency. Thus, a smaller number of samples of measurements leads to shorter latency. However, a smaller number of samples may also affect the accuracy of the positioning.

[0312] In one example, the WTRU may be configured by the network to perform measurements based on M samples of the received PRS resources. However, based on the quality of the measurements, the WTRU may send a request to the network to increase or decrease the number of samples in the measurements. For example, the WTRU may send a request to the network to decrease the number of samples in a measurement if at least one of the following conditions is satisfied: the RSRP of the received PRS is above a (pre)configured threshold; the range or standard deviation in the RSRP of the received PRS is below a (pre)configured threshold; the range or standard deviation in the AoA of the received PRS is below a (pre)configured threshold; the range or standard deviation in the TDOA or ToA of the received PRS is below a (pre)configured threshold; for WTRU-based positioning, the standard deviation or range of the position estimate is below a (pre)configured threshold.

[0313] For example, WTRU may transmit a request to the network to increase the number of samples in a measurement if at least one of the following conditions is satisfied: the RSRP of the received PRS is below a (pre)configured threshold; the range or standard deviation in the RSRP of the received PRS is above a (pre)configured threshold; the range or standard deviation in the AoA of the received PRS is above a (pre)configured threshold; the range or standard deviation in the TDOA or ToA of the received PRS is above a (pre)configured threshold; for WTRU-based positioning, the standard deviation or range of the position estimate is above a (pre)configured threshold.

[0314] The number of reports for on-demand PRS requests can be adjusted. Once a request is approved by the network, the WTRU can determine the number of measurement reports. For example, the WTRU can decide to increase or decrease the number of reports if the number of samples in a measurement report decreases or increases. For example, the WTRU can be configured to send 10 reports with 2 measurement samples per report. If an on-demand request to increase the number of samples to 4 is approved by the network, the WTRU can decrease the number of measurement reports to 5.

[0315] On-demand requests to change the number of samples in a measurement contribute to a reduction in the latency required for positioning or improve the accuracy of positioning.

[0316] In one embodiment, the WTRU may transmit an on-demand PRS message when it detects one or more triggering conditions associated with configured on-demand PRS criteria. In one embodiment, the WTRU may transmit an on-demand PRS message to a network (LMF and / or gNB) when it detects one or more triggering conditions associated with criteria configured in the WTRU.

[0317] WTRU may receive one or more PRS configurations from a network (e.g., LMF), which can identify periodic, non-periodic, and / or semi-continuous resources for PRS measurements for one or more cells and / or TRPs. WTRU may receive from the configurations an indication of a default PRS configuration to use when performing PRS measurements. For example, the default PRS configuration can identify one or more periodic resources for PRS measurements.

[0318] WTRU may also receive from a network (e.g., LMF) a configuration comprising at least one on-demand PRS criterion, each comprising one or more parameters and a respective threshold (or requirement) for each. The parameters in the on-demand PRS criterion may include, for example, one or more of RSRP, TDoA / RTSD, number of multipaths, and / or positioning QoS parameters (e.g., accuracy, latency).

[0319] WTRU may perform a first set of measurements on one or more configured periodic PRS resources associated with, for example, a (default) PRS configuration. WTRU may determine whether to trigger and / or transmit an on-demand PRS message based on the first set of measurements and at least one on-demand PRS criterion and its respective threshold. When one or more triggering conditions within the on-demand PRS criterion are satisfied, WTRU may transmit an on-demand PRS message to an LMF and / or serving gNB, wherein the message may include one or more of the following: one type of on-demand PRS (e.g., non-periodic PRS, semi-persistent PRS), a cell / TRP (IDs), the urgency of the request, and / or an indication of the on-demand PRS configuration (for the cell / TRP).

[0320] When an acknowledgment message is received by the WTRU—wherein the acknowledgment message may indicate the receipt of an on-demand PRS message from the network and / or the on-demand configuration requested by the WTRU is implemented by the network (e.g., the WTRU may receive a PRS from the requested cell / TRP / gNB)—the WTRU may perform a second set of measurements on one or more resources of the requested or configured on-demand PRS. When performing the measurements, the WTRU may transmit a measurement report (e.g., an LPP message) to the network (e.g., an LMF and / or gNB), wherein the measurement report may include one or more IDs of the requested or configured on-demand PRS that are possibly applied by the WTRU when performing the second set of measurements and / or, for example, the PRS measurements.

[0321] WTRU can perform certain actions when it receives an indication that the requested on-demand PRS is not fulfilled or supported by the network.

[0322] In one embodiment, the WTRU performs one or more actions based on the reception of an indication that an on-demand PRS message transmitted by the WTRU to the network (i.e., LMF and / or gNB) to request a PRS configuration and / or parameters to be changed in the PRS configuration cannot be fulfilled by the network.

[0323] In one example, the WTRU may receive an explicit indication message indicating the rejection of an on-demand PRS message transmitted by the WTRU. In the case of an explicit indication, the WTRU may receive a message that may include a flag (e.g., a binary indication) indicating whether the requested PRS configuration / parameters are fulfilled or not. For example, when the requested PRS configuration / parameters are supported by the network, the WTRU may receive a flag indicating the value '1' along with the ID of the associated PRS configuration / parameter. Similarly, when the requested PRS configuration / parameters are not supported by the network or are rejected, the WTRU may receive a flag indicating the value '0' along with the ID of the associated PRS configuration / parameter. In another example, the explicit indication may include a reason for rejection indicating why the on-demand PRS does not fulfill / support the PRS configuration / parameters requested by the WTRU. Explicit denial may include other parameters, such as, for example, one or more time duration values ​​(e.g., a prohibit time duration for retransmitting on-demand PRS, a re-evaluation time duration for re-evaluating triggering conditions), triggers for using pre-configured time durations, and / or alternative PRS configurations / parameters that can be applied by the WTRU. The WTRU may receive an explicit indication from the network, for example, in an LPP message, an RRC message, a MAC CE, or a DCI, that indicates a denial of the on-demand PRS.

[0324] In another example, a rejection indication may be implicitly received by the WTRU from the network in one or more of the following: Absence of an explicit indication: For example, when any explicit indication, including a confirmation indication, is not received, possibly for a specified configured time duration, the WTRU may determine that the requested on-demand PRS is rejected. Absence of requested PRS configurations / parameters: For example, when changes to the requested PRS configuration and / or parameters (e.g., periodicity of the PRS, transmission from the TRP) are not received and / or detected based on measurements, the WTRU may determine that the transmitted on-demand PRS is rejected. Reception of alternative PRS configurations / parameters: For example, when the WTRU detects one or more alternative PRS configurations / parameters in the on-demand PRS that are different from those indicated / requested by the WTRU based on measurements of the PRS, the WTRU may determine that the requested on-demand PRS is not fulfilled / supported. In one example, alternative PRS configurations / parameters may be any of the existing PRS configurations / parameters available and / or used by the WTRU before transmitting the on-demand PRS.

[0325] When WTRU receives an explicit and / or implicit indication that an on-demand PRS is not fulfilled, it may perform one or more of the following actions based on the received indication: continue using existing PRS configurations / parameters; fall back to default configurations; resend the on-demand PRS; and / or, in particular, re-evaluate triggering conditions.

[0326] For example, when the WTRU receives a rejection, it may continue to perform measurements using the existing PRS configuration / parameters. Possibly, when a time duration value is displayed along with the rejection, the WTRU may start a timer when the rejection is received and perform measurements using the existing / displayed PRS configuration / parameters after the expiration of the timer, which runs over the displayed timer duration value.

[0327] For example, WTRU may be pre-configured with one or more default PRS configurations and / or parameters of PRS configurations. In this case, when receiving a rejection signal that may indicate a fallback to a default configuration (e.g., having the ID of the configuration), WTRU may use the default PRS configurations / parameters accordingly.

[0328] For example, the WTRU may receive an indication indicating a trigger to apply a prohibition time duration or a pre-configured prohibition time duration, possibly with a denial indication. In this case, the WTRU may start a timer upon receiving the denial indication and, for example, transmit another on-demand PRS upon the expiration of the timer running over the duration of the prohibition time duration.

[0329] For example, the WTRU may receive an indication indicating a trigger to apply a re-evaluation time duration or a pre-configured re-evaluation time duration, possibly accompanied by a rejection indication. In this case, the WTRU may start a timer upon receiving the rejection indication. At the expiration of the timer, which runs over the duration of the re-evaluation time duration, the WTRU may perform measurements using the existing / indicated PRS configuration to determine whether any of the triggering conditions for transmitting an on-demand PRS are detected (e.g., whether the RSRP measured for a PRS resource / beam is below a configured threshold). At least in the event of detecting a triggering condition, the WTRU may transmit an on-demand PRS to the network.

[0330] Although features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with other features and elements. Additionally, the methods described herein may be implemented as computer programs, software, or firmware integrated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, magnetic media such as read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital multifunction disks (DVDs). A processor associated with software may be used to implement a radio frequency transceiver for use in a UE, WTRU, terminal, base station, RNC, or any host computer.

Claims

Claim 1 A method performed by a wireless transmit / receive unit (WTRU), comprising: receiving positioning reference signal (PRS) configuration information; performing a first set of measurements based on the PRS configuration information; determining whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria, wherein the on-demand criteria are based on at least one of reference signal receive power (RSRP), time difference of arrival (TDoA), or number of multipath signals; and transmitting an on-demand PRS request under the condition that the step of determining whether to trigger is positive. Claim 2 A method according to claim 1, wherein the PRS measurements correspond to one or more cells and / or transmission reception points (TRPs). Claim 3 In paragraph 1, the above-mentioned custom PRS standards are additionally based on accuracy, a method. Claim 4 In paragraph 1, the above-mentioned custom PRS standards are additionally based on latency, a method. Claim 5 In claim 1, the above PRS configuration is received from a Location Management Function (LMF). Claim 6 In claim 1, the step of determining whether to trigger the on-demand PRS request is based on one or more configured thresholds. Claim 7 A method according to claim 1, further comprising the step of transmitting to a serving base station or LMF at least one indication of the type of on-demand PRS, cell, transmission and reception point (TRP), urgency of the request, or on-demand PRS configuration. Claim 8 A method according to claim 1, further comprising: a step of performing a second set of measurements on one or more resources of the requested or received on-demand PRS configuration, provided that the confirmation of the request or the on-demand configuration of the request is received; and a step of transmitting a report to a base station or LMF that includes at least the second set of measurements and the ID of the requested or configured on-demand PRS. Claim 9 A WTRU comprising a wireless transceiver unit (WTRU), a receiver configured to receive positioning reference signal (PRS) configuration information; a circuit unit configured to perform a first set of measurements based on the PRS configuration information; a circuit unit configured to determine whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria, wherein the on-demand criteria are based on at least one of reference signal received power (RSRP), time difference of arrival (TDoA), or number of multipath signals; and a transmitter configured to transmit an on-demand PRS request under the condition that the determination to trigger is positive. Claim 10 In paragraph 9, the PRS measurements correspond to one or more cells and / or transmit / receive points (TRPs), WTRU. Claim 11 In paragraph 9, the above PRS configuration is a WTRU received from the location management function (LMF). Claim 12 In paragraph 9, the determination of whether to trigger the on-demand PRS request is based on one or more configured thresholds, WTRU. Claim 13 In paragraph 9, the transmitter is further configured to transmit to a serving base station or LMF at least one indication of the type of on-demand PRS, cell, transmission and reception point (TRP), urgency of the request, or indication of the on-demand PRS configuration. Claim 14 A WTRU according to claim 9, further comprising: a circuit portion configured to perform a second set of measurements on one or more resources of a configured on-demand PRS; and a transmitter configured to transmit a report to a base station or LMF comprising the results of the second set of measurements and an identifier of the configured on-demand PRS. Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete

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