Methods and apparatuses for RIS-aided localization

Abstract

Methods and apparatuses for use of reflective intelligent surfaces in wireless communications are described. The methods include: receiving by a WTRU from a base station a first information and decoding the first information to determine the presence of one or more reflective intelligent surfaces (RIS); requesting second information regarding the RIS; receiving the second information and identifying one or more RIS for localization of the WTRU based on the second information; transmitting to the base station an indication of the identified RIS; receiving a configuration of one or more reference signals for localization; receiving a reference signal for localization and proceeding with localization based on the reference signal; and transmitting a localization report to the base station.

Description

METHODS AND APPARATUSES FOR RIS-AIDED LOCALIZATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 613,986 filed in the U.S. Patent and Trademark Office on December 22, 2023, the entire content of which being incorporated herein by reference as if fully set forth below in its entirety and for all applicable purposes.BACKGROUND

[0002] Localization procedures in 3GPP require multiple cells and the network to coordinate in terms of reference resource transmission and proper wireless transmit receive unit (WTRU) configuration of measurement and reporting For Accurate localization, the transmission / reception points (TRPs) require a tight clock synchronization and phase coherency between them. Currently, the localization frameworks specified in 3GPP do not make use of topological nodes such as relays, repeaters, and reflective intelligent surfaces (RIS). Using these topological nodes instead of a TRP, or in addition to using TRPs, may provide geometric advantages such as reduced synchronization and signaling requirements, and also localization accuracy. The incorporation of reflective intelligent surfaces into a localization framework requires considerations around different RIS capabilities, types, and modes that can impact the system. Moreover, since RIS do not creating signals, methods for WTRU identification of the RIS-aided links are needed.SUMMARY

[0003] Methods performed by a WTRU are described. The methods include receiving, from a base station, first information; decoding the first information to detect one or more reflective intelligent surfaces (RISs); transmitting a request for second information regarding the RISs; receiving the second information from the base station; identifying one or more of the RISs for localization of the WTRU based on the second information; transmitting to the base station an indication of the identified one or more RISs; receiving configuration information of one or more reference signals for localization; based on the configuration information, receiving a reference signal for localization; performing a localization based on the reference signal; and transmitting a localization report based on the localization to the base station.

[0004] In further embodiments, the first information comprises at least one of: RIS identification, RIS coordinates, RIS types, RIS operating mode, RIS minimum power threshold and RIS association with a base station

[0005] In further embodiments, the request for second information includes at least one of: time domain availability of the RIS; frequency domain availability of the RIS; propagation delay between the RIS and thebase station; geo-location information of the RIS and base station; or downlink reference signals and associated transmission configuration indication (TCI) states and quasi co-location information (QCI) for identification of the RIS.

[0006] In further embodiments, the indication of the identification of the RIS to the base station is made via MAC-CE or PUSCH.

[0007] In further embodiments, the received configuration includes one or more of: PRS resource sets, PRS resources, time, frequency resources, comb offset or resource block offset.

[0008] In further embodiments, the localization includes determining a delay between the WTRU and the base station based on at least one of: time of arrival, angle of arrival, reference signal received power, orientation and relative position to source nodes.

[0009] In further embodiments, the localization report includes at least one of: an estimated location of the WTRU relative to the base station, an estimated delay between the WTRU and the base station; received RS resource identification and corresponding measurement, measured metrics of an RIS-aided path between the WTRU and the base station; a preferred source node combination; and a preferred set of RIS.

[0010] An apparatus (e.g., a WTRU) configured to perform any of the above methods is also described.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A more detailed understanding may be had from the detailed description below, given by way of example in conjunction with drawings appended hereto. Figures in such drawings, like the detailed description, are examples. As such, the Figures (FIGs.) and the detailed description are not to be considered limiting, and other equally effective examples are possible and likely. Furthermore, like reference numerals ("ref.") in the FIGs. indicate like elements, and wherein:

[0012] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0013] FIG. 1 B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG 1A according to an embodiment;

[0014] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (ON) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0015] FIG. 1D is a system diagram illustrating a further example RAN and a further example ON that may be used within the communications system illustrated in FIG 1A according to an embodiment;

[0016] FIG. 2 is an illustration of a RIS comprising a RIS-controller and a RIS panel;

[0017] FIG. 3 is a block diagram of an exemplary RIS architecture;

[0018] FIG. 4 is an exemplary signaling diagram for a WTRU configuration to use RIS for localization;

[0019] FIG. 4A is a flow chart of an exemplary process for a WTRU configuration to use RIS for localization;

[0020] FIG. 5 is an exemplary diagram of a WTRU detecting RIS signatures;

[0021] FIG. 6 is an exemplary diagram of WTRU localization based on RSTD aided by RIS; and

[0022] FIG. 7 is an exemplary digram of WTRU selection of RIS nodes for localization.DETAILED DESCRIPTION

[0023] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments and / or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components and circuits have not been described in detail, so as not to obscure the following description. Further, embodiments and examples not specifically described herein may be practiced in lieu of, or in combination with, the embodiments and other examples described, disclosed or otherwise provided explicitly, implicitly and / or inherently (collectively "provided") herein. Although various embodiments are described and / or claimed herein in which an apparatus, system, device, etc. and / or any element thereof carries out an operation, process, algorithm, function, etc. and / or any portion thereof, it is to be understood that any embodiments described and / or claimed herein assume that any apparatus, system, device, etc. and / or any element thereof is configured to carry out any operation, process, algorithm, function, etc. and / or any portion thereof.

[0024] Example Communications System, Networks, and Devices

[0025] The methods, procedures, apparatuses and systems provided herein are well-suited for communications involving both wired and wireless networks. An overview of various types of wireless devices and infrastructure is provided with respect to FIGs. 1A-1D, where various elements of the network may utilize, perform, be arranged in accordance with and / or be adapted and / or configured for the methods, apparatuses and systems provided herein.

[0026] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), singlecarrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform Spread OFDM (ZT-UW-DFT-S- OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0027] As shown in FIG. 1 A, the communications system 100 may include wireless transmit / receive 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, though itwill be appreciated that the disclosed embodiments contemplate 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 By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a station (STA), may be configured to transmit and / or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0028] The communications 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 the CN 106, the Internet 110, and / or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0029] The base station 114a may be part of the RAN 104, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, and the like. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0030] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0031] More specifically, as noted above, the communications 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, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed Uplink (UL) Packet Access (HSUPA).

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0033] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using NR.

[0034] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g , an eNB and a gNB).

[0035] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e , Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0036] The base station 114b in FIG 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the 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 shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106.

[0037] The RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and / or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0038] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or the 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 that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and / or the internet protocol (IP) in the TCP / IP internet protocol suite. The networks 112 may include wired and / or wireless communications networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0039] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1 A may be configured to communicate with the base station 114a, which may employ a cellularbased radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0040] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0041] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or moremicroprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0042] The transmit / receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0043] Although the transmit / receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0044] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit / receive element 122 and to demodulate the signals that are received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0045] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit) The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and / or the removable memory 132. The 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 identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0046] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li- ion), etc.), solar cells, fuel cells, and the like.

[0047] The processor 118 may also be coupled to the 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 in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment

[0048] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a handsfree 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, and the like. The peripherals 138 may include one or more sensors. The sensors may be one or more of 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, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor and the like.

[0049] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e g., associated with particular subframes for both the UL (e.g., for transmission) and DL (e.g., for reception) may be concurrent and / or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e g., for transmission) or the DL (e g., for reception)).

[0050] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0051] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a.

[0052] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0053] The CN 106 shown 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. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0054] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA

[0055] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may 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, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0056] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0057] The CN 106 may facilitate communications with other networks For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers.

[0058] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0059] In representative embodiments, the other network 112 may be a WLAN.

[0060] A WLAN in Infrastructure 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 in to and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA The traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. The peer-to- peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad-hoc” mode of communication.

[0061] When using the 802.11ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the 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. For CSMA / CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0062] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0063] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels The 40 MHz, and / or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0064] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control / Machine- Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g. , only support for) certain and / or limited bandwidths The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0065] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802 11 n, 802.11ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in 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 status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.

[0066] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0067] FIG. 1 D is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0068] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a. 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 theremaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0069] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0070] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with / connect to gNBs 180a, 180b, 180c while also communicating with / connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non- standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, 102c.

[0071] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support of network slicing, DC, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0072] The CN 106 shown in FIG. 1 D 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. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0073] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b,management of the registration area, termination of non-access stratum (NAS) signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and the like The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0074] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0075] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like.

[0076] The CN 106 may facilitate communications with other networks For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0077] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0078] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or in an operator network environment. For example, the one or more emulation devices mayperform the one or more, or all, functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network The emulation device may be directly coupled to another device for purposes of testing and / or performing testing using over-the-air wireless communications.

[0079] The one or more emulation devices may perform the one or more, including all, functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0080] The following abbreviations and acronyms are used interchangeably throughout this written description.ACK AcknowledgementAoA Angle of ArrivalAoD Angle of DepartureARFCN Absolute Radio-Frequency Channel NumberBLER Block Error RateBW BandwidthBWP Bandwidth PartCAP Channel Access PriorityCAPC Channel access priority classCCA Clear Channel AssessmentCCE Control Channel ElementCE Control ElementCG Configured Grant or Cell GroupCORESET Control Resource SetCP Cyclic PrefixCP-OFDM Conventional OFDM (relying on cyclic prefix)CQI Channel Quality IndicatorCRC Cyclic Redundancy CheckCSI Channel State InformationCW Contention WindowCWS Contention Window SizeCO Channel OccupancyDAI Downlink Assignment IndexDCI Downlink Control InformationDFI Downlink feedback informationDG Dynamic grantDL DownlinkDM-RS Demodulation Reference SignalDRB Data Radio BearerDRX Discontinuous ReceptionECID Enhanced Cell ID elea enhanced Licensed Assisted Access ebb enhanced Mobile BroadbandFeLAA Further enhanced Licensed Assisted AccessFT Fourier TransformHARQ Hybrid Automatic Repeat RequestIM Interference MeasurementLAA License Assisted AccessLBT Listen Before T alkLCH Logical ChannelLCP Logical Channel PriorityLBT Listen-Before-T alkLOS Line of SightNLOS Non-Line of SightLMF Location Management FunctionLPP LTE Positioning ProtocolLTE Long Term Evolution e.g., from 3GPP LTE R8 and upMAC CE MAC Control ElementMAC Medium Access ControlMCS Modulation and Coding SchemeMIMO Multiple Input Multiple OutputNACK Negative ACKNAS Non-access stratumNR New RadioOFDM Orthogonal Frequency-Division MultiplexingOTDOA Observed Time Difference of ArrivalPDCCH Physical Downlink Control ChannelPDSCH Physical Downlink Shared ChannelPDU Packet Data UnitPHY Physical LayerPID Process IDPO Paging OccasionPRACH Physical Random Access ChannelPRS Positioning Reference SignalPRU Positioning Reference UnitPSS Primary Synchronization SignalPTRS Phase Tracking Reference SignalPUCCH Physical Uplink Control ChannelPUSCH Physical Uplink Shared ChannelRA Random Access (or procedure)RACH Random Access ChannelRAR Random Access ResponseRCU Radio access network Central UnitRE Resource ElementRF Radio FrequencyRIS Reflective Intelligent SurfaceRLF Radio Link FailureRLM Radio Link MonitoringRNTI Radio Network IdentifierRNA RAN Notification AreaRO RACH occasionRRC Radio Resource ControlRRM Radio Resource ManagementRTT Round Trip TimeRP Reception PointRS Reference SignalRSRP Reference Signal Received PowerRSTD Reference Signal Time DifferenceRTT Round Trip TimeRSSI Received Signal Strength IndicatorRT OA Relative Time of ArrivalSDAP Service data adaptation protocolSDU Service Data UnitSRB Signaling Radio BearerSRS Sounding Reference SignalSS Synchronization SignalSSS Secondary Synchronization SignalSWG Switching Gap (in a self-contained subframe)SPS Semi-persistent schedulingSUL Supplemental UplinkTB Transport BlockTBS T ransport Block SizeTDoA Time Difference of ArrivalToF Time of FlightTRP T ransmission-Reception Point (used interchangeably with GnB)TSC Time-sensitive communicationsTSN Time-sensitive networkingTTI Transmission Time IntervalUCI Uplink Control InformationUL UplinkURLLC Ultra-Reliable and Low Latency CommunicationsWBWP Wide Bandwidth PartWTRU Wireless Transmit Receive UnitWLAN Wireless Local Area Networks and related technologies (IEEE 8O2.xx domain)

[0081] 3GPP has defined various processes for localization for both downlink and uplink, involving the use of multiple cells. Positioning reference signals (PRS) for the DL and sounding reference signal for positioning (SRSp) for the UL may be used. In the DL, the PRS is a one-port signal spanning up to 12 OFDM symbol per slot in time, with a comb frequency multiplexed arrangement to allow for transmitting multiple PRSs from multiple TRPs. In the DL, multiple TRPs transmit the PRS over shared resources, allowing a WTRU to estimate its position based on various positioning measurements (e.g., RSRP, Doppler, DL-TDoA, etc.). SRSp signals are also one-port signals that span up to 14 OFDM symbols in up to full bandwidth and may be transmitted from multiple users in a frequency multiplexed manner for multi-user transmission. In the UL, a WTRU may utilize the SRS signals for positioning, where the WTRU transmits SRS resources towards multiple TRPs, which then perform positioning measurements. Both the UL and DL techniques may combined, where the TRP transmits the PRS in the DL and the WTRU transmits the SRS.

[0082] The following definitions / conditions are used herein: Localization measurements refer to the measurements that determine the localization characteristics of an object, e.g., AoA, TDoA, position, RSRP etc. A WTRU may rely on predefined thresholds that are configured by the gNB. The Dilution of Precision (DoP) is a term used in satellite communication that determines the effect of the position of a set of satellites on the accuracy of positioning measurements. It can be typically measured using a few measurements, such as the Horizontal Dilution of Precision (HDoP), Vertical Dilution of Precision (VDoP), Position Dilution of Precision (PDoP), Time Dilution of Precision (TdoP) and Geometric Dilution of Precision (GDoP). A signature is defined by the set of measurements and configurations that are specific for a topological node. For instance, a signature may include Bol, RSRP, location, RIS relative location, pathloss estimate (alpha value), multipath components pattern (e.g. number of components, power profile, delay profile), etc. A RIS signature is dependent on the WTRU location and capabilities and the WTRU may be required to determine the RIS stamp / signature in order to utilize RIS for localization

[0083] A reflective intelligent surface is a topological node that can actively or passively manipulate the properties of the RF signals that impinge upon it. A RIS may control the properties of a wireless transmission using multipath creation, establishing LOS, beamforming, etc The scattering properties of a RIS are dependent upon the type of RIS used (e.g. passive, active, or hybrid) and its operating mode (e.g., reflection, refractions, joint reflective and transmissive, absorption, or a combination of these).

[0084] A RIS comprises at least a RIS controller 212 and a RIS panel 200, as shown, for example, in FIG. 2. A RIS panel 200 comprises of a group of elements 210, which have the capability to change at least one of the properties of incident radio waves including frequency, amplitude, phase and polarization The radio wave can be at least reflected or transmitted to another direction by the RIS panel, depending on the design of RIS. The RIS micro-controller refers to a component of a RIS, responsible for configuring the RIS elements to achieve a desired manipulation of the incident radio wave, potentially processing any signaling received from another network node. The configuration of a RIS element by the micro-controller is conveyed through controlsignaling from the RIS controller Inside a RIS, one interface is the interface between the RIS micro-controller and RIS panel to transmit the control signals.

[0085] The operating characteristics of a RIS, hereafter called RIS signature, are dependent on the WTRU location and capabilities. The WTRU may be required to determine the RIS signature to utilize a RIS for localization purposes. A RIS signature may include Bandwidth of Influence (Bol), RSRP, location, relative location, pathloss estimate (alpha value), or multipath components pattern (e.g. number of components, power profile, delay profile). Bol is the range of frequencies for which the RIS elements can produce scattering properties, e.g. for a given transmitted signal, the RIS may be able to reflect a portion of the bandwidth of the signal.

[0086] An example system showing RIS controlling strategies is shown in the block diagram of FIG. 3. An example system may be gNB-controlled (through one or more gNBs (TRPs 312)) or WTRU-controlled (by one or more WTRU 310). An example control link between a RIS and a TRP is shown 320. An example control link between a RIS and WTRU is shown 322. An example RIS-aided downlink is shown 326 An example RIS- aided upline is shown 324.

[0087] In embodiments, localization procedures may require multiple cells and the network to coordinate in terms of reference resource transmission and proper WTRU configuration of measurement and reporting, e.g. using PRS, SRSp, etc. For accurate localization, TRPs may require a tight clock synchronization and phase coherency between them

[0088] Described herein are systems and methods for a WTRU to utilize topological nodes in the environment (e.g. RISs) to perform localization with a reduced number of required TRPs / cells.

[0089] In embodiments a WTRU may be configured for RIS-aided localization, receiving RIS-based localization configurations which may include assistance information such as RIS signatures or phase patterns. The WTRU may be further configured to receive reference signals for localization. The WTRU may determine to use one or multiple topological nodes (such as RISs) for localization and proceed with beam signature acquisition from measurements using the reference signals. The WTRU provides the network with indications upon detection or lack of detection of RIS signatures. After determining the reference signals impinging from a RIS with certain signature, the WTRU may use that reference signal received from the RIS-aided path for computing its position, velocity, orientation, etc. The WTRU then reports localization information to the gNB. Additionally, the WTRU may determine and report the preferred source nodes to use for localization, e.g., to achieve high accuracy localization.

[0090] An example signaling flowchartfor capturing WTRU configuration for RIS-aided localization is shown in FIG. 4. At 414, a gNB / TRP 410 may transmit information including available RIS configurations, which may include RIS IDs and RIS information. At 418, a WTRU, 412 may check available information regarding each of the available RIS nodes. At 420, the WTRU may transmit a request for specific RIS information, including, for example, time domain information, frequency domain information and the like. At 422, the gNB / TRP may transmit the requested information.

[0091] A more-detailed example process is shown in FIG. 4A and described herein. In embodiments, at 430 a WTRU may receive and decode a first information to determine the presence of a RIS for support of localization. In embodiments, the first information may be received from a broadcast channel, e.g., PBCH, or a SIB in a PDSCH, or through higher-layer signaling, e g., RRC or MAC-CE. The first information may include: RIS related information, e.g., RIS IDs, RIS coordinates, RIS types, RIS operating mode, minimum receive power threshold, RIS ID association with TRP ID, and the like.

[0092] At 432, based on its capability, the WTRU may request a second information which may include: a) time domain availability of RIS units, e.g., indicators for available symbols, slots, radio frames, etc - from this information, a WTRU may determine RIS_activated and RIS-deactivated periods - the time domain availability may be defined by a configurable pattern which it may always hold or activated / deactivated - alternatively, the pattern may be indicated dynamically based on WTRU’s request; b) frequency domain availability of RIS, e.g., frequency band (FR1 , FR2, etc.), BW part, etc; c) a set of time values indicating the propagation delay between aTRP and one or more RIS units, for example; d) propagation delay set 1 : {t_delay_TRP1 -RIS 1 , _delay_TRP1- RIS2}, Propagation delay set 2: {t_delay_TRP2-RIS 1 , _delay_TRP2-RIS2); e) geo-location information of the serving TRP and RIS units; and / or f) one or more set of downlink reference signals and the associated TCI states containing QCL information for identification of preferred set of RISs.

[0093] At 434, the WTRU may receive a second information and based on one or more of information elements in the second information, e.g., configured referenced signal and pattern of RIS availability, the WTRU identifies one or more RISs that may be used for localization

[0094] At 436, the WTRU indicates to the serving TRP the identified RIS(s), i.e., a RIS detection report via MAC-CE, PUSCH, and the like.

[0095] At 438, the WTRU receives a configuration of one or more reference signals for localization (PRS resource sets, PRS resources, time, frequency resources, comb offset, RB offset, and the like.).

[0096] At 440, the WTRU receives a RS for localization and proceeds with localization with the aid of the identified RIS. In an embodiment, the WTRU may use the activation / deactivation pattern of the RIS to determine the direct link delay between the gNB and the WTRU For example, when the RIS is in a de-activated state a WTRU may estimate the propagation delay using a configured RS. Similarly, when the RIS is in an activated state a WTRU may estimate the propagation delay using the configured RS. Based on the delay the information, a WTRU estimates its position by using the estimated delays, indicated TRP-RIS delay values, and geo-location information of the serving TRP and the available RIS. In an embodiment, a process may involve, TDoA, AoA, or other localization methods based on location, velocity, ToA, AoA, RSRP, orientation, relative position to the source nodes, and the like, based on the measurements from the direct and RIS-aided paths.

[0097] At 442, the WTRU sends the RIS-aided localization report to the gNB which may include any or all of the following: a) the WTRU’s estimated location to the gNB; b) the WTRU’s estimated delay values to the gNB to indicate its location information; alternatively, c) a WTRU may only report the difference between the estimated delays; d) received RS resource ID(s) and the corresponding measurements (e.g., received RSRP,AoA, ToA), LoS / NLoS ID per entity, pathloss estimate (alpha value) etc; e) measured metrics of the RIS-aided path, such as strength, AoA, AoD, received RS resource ID(s), received RSRP, Bol, LoS / NLoS ID per entity, pathloss estimate (alpha value), and the like; f) the best source nodes combination for obtaining the position based on a specific threshold, e.g., calculates the dilution of precision (DoP) of each possible combination of the source nodes; and / or g) a preferred set of RIS to perform localization in a future transmission.

[0098] Embodiments described herein enable using topological nodes, including one or more RISs, in assisting for localization. In existing systems, multiple TRPs are required for performing localization. This requires a tight clock synchronization between and phase coherency TRPs. However, in the described embodiments, a WTRU may use existing topological nodes to perform localization measurements, which does not require any synchronization between TRPs.

[0099] In embodiments, a WTRU may receive and decode a network request through RRC signaling to provide capability information. In an embodiment, a WTRU may receive and decode the request following the random-access procedure. The WTRU may prepare a capability information message including capability for localization with the aid of RIS(s). The WTRU sends the WTRU capability information message through RRC, e.g., over the PUSCH. WTRU capability information is then used by the network to optimize its configuration and resource allocation for localization. The WTRU may be configured by the network (e.g., gNB, LMF) to perform localization with the aid of a single RIS or multiple RISs using RRC, MAC-CE, or DCI.

[0100] WTRU resources for localization are described herein. Localization resources may include one or more of the following: a) a set of RIS(s), e.g., in the form of RIS ID(s); b) a set of TRP(s), e.g., in the form of TRP ID(s); a set of RIS / TRP signature(s); c) a set of reference signals, e.g., in the form of RS resource ID(s), RS resource set I D(s), etc.; and / or d) a set of spatial parameters, such as beams, TCI states, etc., e.g , in the form of TCI state I D(s), ID(s) of source RS(s), etc.

[0101] A WTRU may determine that a WTRU request for localization resources is to be transmitted. The determination may be based on the WTRU implementation or may be described in a technical specification. In some cases, the determination may be based on a configuration the WTRU has received. In further embodiments, the determination may be based on measurements of configured reference signal(s).

[0102] In embodiments, a WTRU may have received a configuration comprising a criterion for when to transmit a WTRU request for RIS information. The criterion may comprise a localization accuracy metric. For example, the WTRU may transmit a request for localization resources if the localization accuracy is above a threshold that may be configurable The criterion may comprise a localization change metric. For example, the WTRU may transmit a request for localization resources if the WTRU localization or position has changed by more than a threshold, which may be configurable, since the time the WTRU transmitted the previous WTRU request. In embodiments, a timer may be associated with the criterion that may be started when a WTRU request is transmitted, and the WTRU may be prohibited from transmitting another request until the timer has expired.

[0103] In embodiments, the WTRU request for localization resources may comprise a request to add a set of localization resources and / or a request to release a set of (previously added) localization resources.

[0104] Based on the first and / or second information, in embodiments, the WTRU may determine a set of localization resources that may be used for localization. The WTRU may include the determined set of localization resources in the WTRU request for localization resources.

[0105] In embodiments, the network may configure one or more candidate sets of localization resources. The WTRU request for localization resources may comprise an indication of one or more candidate sets of localization resources. The WTRU request for localization resources may be transmitted, for example, as an RRC message (e.g., in a PUSCH), a MAC CE (e g., in a PUSCH), a UCI (e.g., in a PUSCH or PUCCH).

[0106] Upon transmission of the WTRU request for localization resources, the WTRU may receive a configuration, activation, and / or, indication.

[0107] In one example, the WTRU may send a request to the network (e.g., LMF, gNB, or other entity that configures reference signals to the WTRU) for DL RS configuration (e.g., DL-PRS configuration) in the uplink physical channels, e.g , PUSCH or PUCCH, via higher layer signaling e.g., MAC-CE or RRC, or via LPP messages.

[0108] In one example, the WTRU may receive the DL-PRS configuration from the network (e.g , LMF, gNB). The configurations may consist of one or more of the following: a) TRP ID(s); b) DL-PRS resource set ID; c) DL-PRS resource ID List; d) time configurations: including slot offset (e.g , relative to the reference time (e g., frame, sub-frame, slot, symbol index, etc.), the reference time may be a triggering DCI or MAC-CE signal); e) starting symbol position, and / or Number of symbols; f) frequency configurations including: comb offset values; cyclic shift values; starting RE position in frequency; number of RBs; repetition configurations including: Resource Type (e.g., aperiodic, semi-persistent, periodic) and / or resource set periodicity for periodic and semi- persistent types; and / or g) other configurations including: power control configurations (e.g , default transmission power) and pathloss configurations associated with a reference signal (e.g., DL-PRS, SS-block).

[0109] In embodiments, a WTRU may determine to perform localization with the aid of a single or multiple source nodes (e.g. gNB / TRP, RIS, etc), among which the signatures of some of these some source nodes were not obtained by the WTRU For a RIS for which the WTRU acquired its signature(s), that is assigned for localization, the WTRU may request beam signature acquisition, e.g. WTRU learning about the RIS, for the new RIS, e.g., new localization resource, or RISs, e.g., existing localization resource.

[0110] In embodiments, the WTRU may receive configurations about the set of beams for acquiring the signatures e.g., one or more set of TCI states containing QCL information, reference signal type, time / frequency resource allocation, bandwidth, measurements to perform, dynamic beam training window, RIS ID, start time, duration, signature types etc.), e.g., via RRC configuration, DCI, MAC-CE. The configuration may associate reference signals, TCI states, etc., with RIS ID(s).

[0111] In embodiments, a gNB may transmit a single or multiple beams towards a single or multiple RISs. In case of training multiple RIS nodes, the gNB may transmit multiple beams towards multiple RISs simultaneously, e.g. beams may be multiplexed over non-overlapping frequency resources or frequency staggered resources. The reflected signal from each topological node, e.g. RIS, will bear the distinctive characteristics of that node. The exemplary illustration in FIG. 5 shows a single gNB 500 transmitting a signal to a WTRU 510. The transmitted signal (516, 517) is reflected by two different RISs 512 514. It can be seen in this figure that the reflected signal at each RIS (518, 519, respectively) holds the signature of that particular RIS (512, 514).

[0112] In embodiments, a WTRU may receive reference signals (e.g. PRS, CSI-RS, SSB, etc.) per RIS and perform measurements to determine the RIS’s specific signature The WTRU may determine and calculate a set of RIS signatures or components of a RIS signature, e.g., Bol, RSRP, RIS location, RIS relative location, pathloss estimate (alpha value), multipath components pattern (e.g. number of multipath component, power profiles), and the like. The Bol may be determined by calculating the relative bandwidth of the received signal (e g. this may be calculated by obtaining the power spectral density of the multipath components then compared to the bandwidth of the transmitted signal). In an embodiment, the WTRU may obtain the channel response of the received signal, e.g. channel impulse response (CIR), power delay profile (PDP), channel frequency response (CFR) The WTRU may perform FT on the CIRs to determine its frequency profile (e.g., Bol).

[0113] After determining the relevant signatures, the WTRU may associate the signatures with the corresponding RIS I D(s). In embodiments, the WTRU may disregard a specific source node, e.g. for example when the measured RSRP does not meet a specific threshold.

[0114] The WTRU may prepare and send a RIS training report to the gNB (e.g., RIS ID / TRP ID, received RS resource ID(s) and the corresponding signature training measurements e.g., measured RSRP, Bol, LoS / NLoS property per entity, pathloss estimate (alpha value), and the like.

[0115] In embodiments, the WTRU may indicate to the gNB that the signatures that have been acquired or the WTRU needs more training, e.g., in the form of an additional WTRU request for localization resources. For example, in case the WTRU requires additional beam training for RIS discovery, a new set of beams is requested from the gNB. In another solution, the WTRU may receive an indication from the network to stop the beam training (e.g., DCI / MAC-CE indication) for RIS discovery.

[0116] WTRU localization with the aid of RIS is described herein. In embodiments a WTRU may be configured by the network (e.g., gNB, LM F) to perform localization with the aid of a single RIS or multiple RISs by the network using RRC, MAC-CE, or DOI. The WTRU may detect the presence of one or more reference signals for localization in the received signal, e.g., based on the configured information about available PRS beams and PRS time / frequency resources. In some cases, the WTRU may perform blind detection of reference signals for localization.

[0117] If the WTRU is configured or determined to perform RSTD localization aided by RISs, the WTRU may perform the following steps as shown, for example in FIG. 6 on time line 630 for each of the identifiedRISs. In an example embodiment, a WTRU 614 may estimate a first propagation delay from a serving TRP 610 by detecting a first ToA of the reference signals for localization measured during the time interval (t1 620 in FIG. 6), where the RIS is in RIS_deactivated state.

[0118] The WTRU may estimate a second propagation delay from the serving TRP by detecting a second ToA (t2 in FIG. 6). of the reference signals for localization measured during the time interval where the RIS is in RIS_activated state

[0119] Based on the first and second propagation delay values, the WTRU may estimate its location with the aid of the configured propagation delay between the serving TRP and the RIS unit, e g., t_delay_TRP-RIS (624 in FIG 6) and geo-location information of TRP and RIS

[0120] In embodiments, the WTRU may obtain the absolute magnitude of the time difference between the first and second ToA, and obtain the corresponding spatial difference, e.g., by multiplying it with the value of the speed of light in vacuum.

[0121] Based on the spatial difference, the WTRU may determine a hyperbola whose focal points are determined by the TRP and RIS location, and whose distances to the focal points differ by a value equal to the obtained spatial difference.

[0122] The WTRU may repeat the above steps to further determine additional hyperbolas whose intersection may determine the WTRU location.

[0123] If the WTRU is configured or determined to perform AoA-based localization aided by RIS, the WTRU may perform the following steps for each of the RISs identified or selected for localization: The WTRU may estimate a first AoA on the signal from the serving TRP measured during the time interval where the RIS is in RIS_deactivated state. The WTRU may estimate a second AoA on the signal from the serving TRP measured during the time interval where the RIS is in RIS_activated state. The first and the second AoA may be measured with respect to a WTRU orientation vector, e.g., a vector perpendicular to the receive antenna panel or any other predefined WTRU surface whose coordinates can also be reported, and may be expressed as, e.g., indexes in a table of predefined directions The WTRU may estimate its location based on the first and second AoA and the geo-location information of TRP and RIS. In embodiments, the WTRU may determine two lines stemming respectively from the TRP and RIS with directions given by the first and second AoAs, respectively, whose intersection may determine the WTRU location.

[0124] If the WTRU is configured or determined to perform ToA and AoA-based localization aided by RIS(s), the WTRU may use any combination of ToA and AoA measurements to infer its location. In embodiments, the WTRU may determine one or more hyperbolas based on the measured RSTD with focal points respectively given by the location of the TRP and the RISs involved, and one or more lines stemming from the TRP and any of the RIS units at the directions given by their measured AoAs, whose intersection may determine the WTRU location. Other embodiments may include additional metrics, e.g., RSRP, speed, orientation, etc. aided by measurements from the direct and the RIS-aided paths according to the WTRU capabilities.

[0125] In embodiments, the WTRU may further estimate the accuracy of the ToA and AoA measurements performed for each of the identified RISs, e.g., as given by its error variance. In embodiments, the WTRU may obtain a dilution of precision value based on the known geo-location information.

[0126] WTRU localization reporting is described herein. A WTRU following localization measurements with the aid of RIS may report at least one of the following to the network: a) WTRU's estimated location; b) the WTRU’s measured delay values, (e.g., 620, 622 of FIG. 6) to gNB to indicate its location information. In an embodiment, the delay values may be reported as an absolute values, for e.g., the values as measured by the WTRU In another example, the delay values may be reported as a value relative to an absolute reference delay measurement (e.g., associated with the LoS path, first arrival path, etc.). In such case, the WTRU may report the absolute value corresponding to the reference delay and the relative delay values; c) received RS resource ID(s) and the corresponding measurements (e.g., received RSRP, AoA, ToA), LoS / NLoS ID per entity, pathloss estimate (alpha value) etc; RIS ID(s) and / or the TRP ID(s) associated with the measurements— in embodiments, the WTRU may measure each DL RS(s) (e.g., DL-PRS) directly from one or more TRP(s) and / or reflected through the RIS(s). The WTRU may, in embodiments, associate the measurements with the information of the source (e.g., TRP(s), RIS(s)). This association may be done with the help of the ID(s) associated with the source; d) Measured metrics of the RIS-aided path, such as strength, AoA, AoD, received RS resource ID(s), received RSRP, Bol, LoS / NLoS ID per entity, pathloss estimate (alpha value), etc.; e) the best source nodes combination for obtaining the position based on a specific threshold, e.g., calculates the dilution of precision (DoP) of each possible combination of the source nodes; and / or f) a preferred set of RIS to perform localization in a future transmission.

[0127] In embodiments, the WTRU may use one or more of UCI, MAC-CE, RRC, LPP messages and the like to forward the measurement report to the network.

[0128] WTRU selection of RIS nodes is described herein. A WTRU may select and report the best combination of RIS nodes to be used for localization in a future transmission The selection may be based on a set of gNB / TRPs, RISs, etc, with certain measurements, such as the DoP. The DoP measurements may be determined for each possible combination of topological nodes based on the coordinates of each node with respect to the WTRU.

[0129] Given a specific combination of topological nodes, e.g., shown in FIG. 7, the WTRU uses the coordinates of each of the RIS nodes to produce its corresponding DoP coefficients. FIG. 7 shows a WTRU 720 in a configuration with a gNB / TRP 710 and four RIS nodes, 731, 732, 733 an 734. For the nth node out of N nodes these coefficients are defined as an l— sin 9ncos <pn, an 2— cos 0ncos <pnand an 3= sinn,denote the local azimuth and elevation angles of the nodes with respect to the WTRU

[0130] In an example, the WTRU then generates the DoP matrix, which is defined as

[0140] Based on a soecific threshold for each DoP measurements, the WRRU mav select a combination of RIS nodes for localization in a future transmission. For instance, when the DoP measurements of specific combination of RIS nodes is above a specific threshold, the WTRU considers the combination as “valid” for future RIS-aided localization operations. The WTRU may obtain multiple combinations as “valid” for future measurements, or may select a single combination, e.g. the one with the highest DoP measurements. This combination may be included as part of the RIS-aided localization report.

[0141] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magnetooptical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMSWhat is Claimed:

1. A method performed by a wireless transmit receive unit (WTRU) for wireless communications, the method comprising: receiving, from a base station, first information; decoding the first information to detect one or more reflective intelligent surfaces (RISs); transmitting a request for second information regarding the RISs; receiving the second information from the base station; identifying one or more of the RISs for localization of the WTRU based on the second information; transmitting to the base station an indication of the identified one or more RISs; receiving configuration information of one or more reference signals for localization; based on the configuration information, receiving a reference signal for localization; performing a localization based on the reference signal; and transmitting a localization report based on the localization to the base station.

2. The method of claim 1 , wherein the first information comprises at least one of: RIS identification, RIS coordinates, RIS types, RIS operating mode, RIS minimum power threshold and RIS association with the base station.

3. The method of claim 1 or 2, wherein the request for second information includes at least one of: time domain availability of the RIS; frequency domain availability of the RIS; propagation delay between the RIS and the base station; geo-location information of the RIS and the base station; or downlink reference signals and associated transmission configuration indication (TCI) states and quasi colocation information (QCI) for identification of the RIS.

4. The method of any of claims 1 to 3, wherein the indication of the identified RIS is made via a medium access control control element (MAC-CE) or physical uplink shared channel PUSCH).

5. The method of any of claims 1 to 4, wherein the received configuration includes one or more of: positioning reference signal (PRS) resource sets, PRS resources, time, frequency resources, comb offset or resource block offset.

6. The method of any of claims 1 to 5, wherein the localization includes determining a delay between the WTRU and the base station based on at least one of: time of arrival, angle of arrival, reference signal received power, orientation and relative position to source nodes.

7. The method of and of claims 1 to 6, wherein the localization report includes at least one of: an estimated location of the WTRU relative to the base station, an estimated delay between the WTRU and the base station; received RS resource identification and corresponding measurement, measured metrics of anRlS-aided path between the WTRU and the base station; a preferred source node combination; and a preferred set of RIS.

8. A wireless transmit receive unit (WTRU) for wireless communications, the WTRU comprising: a receiver, a transmitter, and a processor configured to: receive, from a base station, first information; decode the first information to detect one or more reflective intelligent surfaces (RISs); transmit a request for second information regarding the RISs; receive the second information from the base station; identify one or more of the RISs for localization of the WTRU based on the second information; transmit to the base station an indication of the identified one or more RISs; receive configuration information of one or more reference signals for localization; based on the configuration information, receive a reference signal for localization; perform a localization based on the reference signal; and transmit a localization report based on the localization to the base station.

9. The WTRU of claim 8, wherein the first information comprises one or more of: RIS identification, RIS coordinates, RIS types, RIS operating mode, RIS minimum power threshold and RIS association with the base station.

10. The WTRU of claim 8 or 9, wherein the request for second information includes at least one of: time domain availability of the RIS; frequency domain availability of the RIS; propagation delay between the RIS and the base station; geo-location information of the RIS and base station; or downlink reference signals and associated transmission configuration indication (TCI) states and quasi co-location information (QCI) for identification of the RIS.

11. The WTRU of any of claims 8 to 10, wherein the indication of the identification of the RIS to the base station is made via MAC-CE or PUSCH.

12. The WTRU of any of claims 8 to 11 , wherein the received configuration includes one or more of: PRS resource sets, PRS resources, time, frequency resources, comb offset or resource block offset13. The WTRU of any of claims 8 to 12, wherein the localization includes determining a delay between the WTRU and the base station based on at least one of: time of arrival, angle of arrival, reference signal received power, orientation and relative position to source nodes.

14. The WTRU of any of claims 8 to 13, wherein the localization report includes at least one of: an estimated location of the WTRU relative to the base station, an estimated delay between the WTRU and the base station; received RS resource identification and corresponding measurement, measuredmetrics of an RIS-aided path between the WTRU and the base station; a preferred source node combination; and a preferred set of RIS.

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