Methods and procedures for scatterers and clutter identification in bistatic sensing

Abstract

A wireless transmit / receive unit (WTRU) may send an indication that the WTRU has the capability to detect and / or report scatterer and / or clutter information. The WTRU may receive first configuration information associated with scatterer and / or clutter information. The WTRU may receive second configuration information associated with reference signals (RS) resources and / or antenna ports used to report the scatterer and / or clutter information. The first configuration information may indicate one or more triggering conditions. The WTRU may determine a plurality of channel impulse responses (CIRs) based on the second configuration information. The WTRU may determine to group the CIRs into one or more CIR resource sets based on the one or more triggering conditions. The WTRU may send a report comprising the scatterer and / or clutter information associated with the antenna ports for each of the one or more CIR resource sets.

Description

METHODS AND PROCEDURES FOR SCATTERERS AND CLUTTER IDENTIFICATION IN BISTATIC SENSINGCROSS-REFERENCE TO RELATED APPLICATIONS[OOOIJThis application claims priority to U.S. Provisional Patent Application No, 63 / 613,439, filed December 21 , 2023, the entire contents of which are incorporated herein by reference.BACKGROUND

[0002] This disclosure relates to methods and / or procedures for bistatic and / or multistatic sensing using wireless signals in a cellular environment.SUMMARY

[0003] A wireless transmit / receive unit (WTRU) may send an indication that the WTRU has the capability to detect and / or report scatterer and / or clutter information. The WTRU may receive first configuration information associated with scatterer and / or clutter information. The WTRU may receive second configuration information associated with reference signals (RS) resources and / or antenna ports used to report the scatterer and / or clutter information. The first configuration information may indicate one or more triggering conditions. The WTRU may determine a plurality of channel impulse responses (CIRs) based on the second configuration information. The WTRU may determine to group the CIRs into one or more CIR resource sets based on the one or more triggering conditions. The WTRU may send a report comprising the scatterer and / or clutter information associated with the antenna ports for each of the one or more CIR resource sets.

[0004] The triggering conditions may comprise an angle of arrival (AoA) of the CIRs being within a threshold angle and / or a signal-to-noise ratio (SNR) of a CIR exceeding a threshold SNR.

[0005] The CIRs of a CIR resource set may be characterized by one or more angles of arrival (AoAs) that are within a threshold range of angles of one another. The WTRU may determine to group the antenna ports whose AoA values are within a threshold range of one another into an antenna port group. The WTRY may assign one or moreantenna port groups to the CIR resource set. The WTRU may identify an emitter source of secondary reflections based on the one or more CIR resource sets.

[0006] The scatterer and / or clutter information may comprises, for each CIR resource set, one or more of an indication of antenna port groups associated with the CIR resource set, a time stamp associated with the CIR resource set, a clutter identifier associated with the CIR resource set, and / or a scatterer identifier associated with the CIR resource set. The clutter identifier may indicate one or more of measurements associated with the CIRs of the CIR resource set, a measurement accuracy associated with the CIRs of the CIR resource set, a clutter type associated the CIR resource set, and / or a confidence level associated with the CIR resource set. The scatterer identifier may indicate one or more of emitter sources associated with the CIRs of the CIR resource set, a sensing measurement associated with the CIRs of the CIR resource set, a measurement accuracy associated with the CIRs of the CIR resource set, and / or a delay difference between antenna port groups associated with the CIR resource set.

[0007] The sensing measurements associated with the CIRs of the CIR resource set may comprise one or more of time of arrival (ToA), time difference of arrival (TDoA), angle of arrival (AoA), absolute and / or relative reference signal received power (RSRP), received signal code power, multipath component in the power delay profile (PDP), doppler spectrum, or radar cross-section. The WTRU may perform sensing measurements on peaks of the CIRs of the CIR resource sets that are not associated with secondary reflections. The WTRU may estimate, based on the performed sensing measurements, the location or speed of one or more objects from which the secondary reflections are reflected.

[0008] The WTRU may determine, after sending the report, whether the one more triggering conditions are associated with newly identified or updated scatterer and clutter information. The WTRU may perform sensing measurements based on the triggering conditions being associated with newly identified or updated scatterer and clutter information. The WTRU may determine, based on the performed sensing measurements, newly identified or updated scatter and clutter information. The WTRU may send an updated report comprising a time stamp and characteristics associated with the newly identified or updated scatterer and clutter information.

[0009] Herein described are devices and / or methods in bistatic sensing to associate scatterers with groups of antenna ports for sensing; discriminate scatterers from clutter; identify the emitter source of the reflections; and / or report the characteristics of scatterers and / or clutter.

[0010] The user equipment (UE), also referred to herein as a wireless transmit / receive unit (WTRU), may send a capabilities message about the support of scatterers and / or clutter identification and / or reporting, e.g., during initial access or upon network request. Based on the capabilities message, the WTRU may be configured and / or determined to characterize and / or report scatterers and / or clutter sources based on configured triggering conditions.

[0011] The WTRU may estimate the channel impulse responses (CIRs) at the available antenna ports. The WTRU may group CIRs into CIR resource sets based on the commonalities between the sensing measurements of the scatterers therein. CIR resource sets may be characterized by one or more antenna port groups each comprising a TRP and / or the antenna ports that share the same TRP and beam for sensing. The WTRU may discriminate the scatterers and / or clutter sources in each CIR resource set and / or determine the emitter sources of the reflections based on configured rules. The WTRU may send a scatterers report containing, for each CIR resource set, the antenna port groups involved, time stamp, identified scatterers and / or clutter sources, sensing measurements performed and / or their confidence levels, etc. The WTRU may check the measurements and / or reports to determine if they need updating based on configured triggers. The WTRU may terminate the procedure upon fulfilment of preconfigured conditions.BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0016] FIG. 2 depicts an example diagram of monostatic sensing performed by a TRP.

[0017] FIG. 3 depicts an example diagram of bistatic sensing involving a TRP and a WTRU.

[0018] FIG. 4 depicts an example diagram of multistatic sensing involving a TRP and multiple WTRUs.

[0019] FIG. 5 depicts an example of CIR peaks produced by sea clutter.

[0020] FIG. 6 depicts an example of bistatic sensing scenario with two sensing transmitters, one sensing receiver, three scatterers, and three clutter sources.

[0021] FIG. 7 depicts an example of CIR peaks in a two-TRP scenario received from antenna port groups ki and k2 showing the contributions from scatterers 1 , 2 and 3 and clutter sources 1 , 2 and 3.

[0022] FIG. 8 depicts an example of CIR peaks in a single-TRP scenario showing an intended scattererj.

[0023] FIG. 9 depicts an illustration of the contents of a scatterers and clutter identification report.

[0024] FIG. 10 depicts an illustration of the contents of a scatterers and clutter identification update.

[0025] FIG. 11 depicts an example flowchart of a wireless transmit / receive unit (WTRU) and TRP actions for scatterers and clutter identification.DETAILED DESCRIPTION

[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 communicationssystem 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), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0027] As shown in FIG. 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will 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” and / or a “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 subscriptionbased 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 headmounted 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 WTRU.

[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 CN106 / 115, 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 Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a 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 / 113, 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, etc. 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 / 113 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 115 / 116 / 117 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 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 New Radio (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., a 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 1 X, 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 WTRUs102c, 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 / 115.

[0037] The RAN 104 / 113 may be in communication with the CN 106 / 115, 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 / 115 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 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may be utilizing a NR radio technology, the CN 106 / 115 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 / 115 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. Thenetworks 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 / 113 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 11 a, which may employ a cellular-based 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 subcombination 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 more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, 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 lightemitting 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), readonly 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 memorystick, 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 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, 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 touchsensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[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 downlink (e.g., for reception) may be concurrent and / or simultaneous. The full duplex radio may include an interference management unit 139 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 WRTU 102 may include a halfduplex 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 downlink (e.g., for reception)).

[0050] FIG. 10 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-Bs 160a, 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. 10, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0053] The CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, itwill 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 an 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 802.11 e DLS or an 802.11 z 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 via signaling. 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 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 non-contiguous 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 802.11 ah relative to those used in 802.11 n, and 802.11 ac. 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, 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, 802.11 ac, 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 allSTAs 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, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[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 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0068] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 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 the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c mayimplement 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 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, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane informationtowards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0072] The CN 115 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 each of the foregoing elements are depicted as part of the CN 115, 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 113 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 PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of 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 machine type communication (MTC) access, and / or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 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 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 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 WTRU IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink 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 113 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 downlink packets, providing mobility anchoring, and the like.

[0076] The CN 115 may facilitate communications with other networks. For example, the CN 115 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 115 and the PSTN 108. In addition, the CN 115 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 Data Network (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 Figures 1 A-1 D, and the corresponding description of Figures 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-ab, 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 may perform 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 wirelesscommunication network. The emulation device may be directly coupled to another device for purposes of testing and / or may 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] Herein described are devices and / or methods in bistatic sensing to associate scatterers with groups of antenna ports for sensing; discriminate scatterers from clutter; identify the emitter source of the reflections; and / or report the characteristics of scatterers and / or clutter.

[0081] The user equipment (UE), also referred to herein as a wireless transmit / receive unit (WTRU), may send a capabilities message about the support of scatterers and / or clutter identification and / or reporting, e.g., during initial access or upon network request. Based on the capabilities message, the WTRU may be configured and / or determined to characterize and / or report scatterers and / or clutter sources based on configured triggering conditions.

[0082] The WTRU may estimate the channel impulse responses (CIRs) at the available antenna ports. The WTRU may group CIRs into CIR resource sets based on the commonalities between the sensing measurements of the scatterers therein. CIR resource sets may be characterized by one or more antenna port groups each comprising a TRP and / or the antenna ports that share the same TRP and beam for sensing. The WTRU may discriminate the scatterers and / or clutter sources in each CIR resource set and / or determine the emitter sources of the reflections based on configured rules. The WTRU may send a scatterers report containing, for each CIR resource set, the antenna port groups involved, time stamp, identified scatterers and / orclutter sources, sensing measurements performed and / or their confidence levels, etc. The WTRU may check the measurements and / or reports to determine if they need updating based on configured triggers. The WTRU may terminate the procedure upon fulfilment of preconfigured conditions.

[0083] Upon receipt, the WTRU may perform one or more of the following actions: the WTRU may send a capabilities message on the support of scatterers and / or clutter identification, e.g., during initial access and / or upon network request. The WTRU may receive a configuration information on scatterers and / or clutter identification and / or reporting. The WTRU may obtain CIRs at the available reference signal (RS) resources and / or antenna ports.

[0084] The WTRU may evaluate triggering conditions and / or group CIR responses in CIR resource sets according to one or more of the following steps: the WTRU may identify CIR peaks having powers and / or signal to noise ratios (SNRs) above a configured threshold. The WTRU may then measure angle of arrivals (AoAs) and / or check the presence of a first set of CIR peaks in the same TRP and / or beam sharing similar AoAs within the configured tolerance. In such case, the WTRU may create a new CIR resource set comprising the antenna ports in the corresponding antenna port group.

[0085] The WTRU may check a second set of CIR peaks whose AoAs may be similar to those CIR peaks in the first set within the configured AoA tolerance for antenna ports in a different TRP and beam. In such case, the WTRU may add a new antenna port group to the CIR resource set with the corresponding antenna ports. The WTRU may then repeat the above steps until all CIR peaks are associated with at least one CIR resource set.

[0086] For each CIR resource set, the WTRU may characterize scatterers and / or clutter for all antenna port groups according to one of more of the following: the WTRU may identify clutter sources by comparison of their measurements with the clutter characteristics. The WTRU may find a third set of CIR peaks not corresponding to any clutter and / or line of sight (LOS) component whose powers exceed a threshold and / or have similar AoAs and times of arrival (ToAs) e.g., within their configured tolerances) within a given antenna port group.

[0087] The WTRU may check if a fourth set of CIR peaks exists for a different antenna port group with similar AoAs and / or inter-arrival times as the third set of CIR peaks, and / or whose ToAs are shifted by a certain delay difference with respect to the third set of CIR peaks. If so, the WTRU may assign a single scatterer ID to the earliest CIR peak in the third and fourth sets of CIR peaks. The WTRU may further consider additional peaks as secondary reflections. The WTRU may record the relative delay difference as characteristic of the scatterer that acts as the emitter source. Otherwise, the WTRU may assign different scatterer IDs to the CIR peaks identified and / or label their emitter sources as unknown.

[0088] The WTRU may perform additional sensing measurements on CIR peaks that are not secondary reflections. The WTRU may send scatterers and / or clutter report containing, for each CIR resource set, their antenna port groups; measurement time stamp; clutter IDs and / or scatterer IDs; their emitter sources; and / or their sensing measurements and / or accuracies. The WTRU may assess the need of an updated report based on configured thresholds for the maximum change in CIR responses, maximum velocity, etc. If triggered, the WTRU may send an updated report containing any updated and / or newly identified scatterers and / or clutter sources. The WTRU may assess a termination condition based on configured thresholds. If triggered, the WTRU may terminate measurements and / or transmit a control indication to the network.

[0089] Without loss of generality, the term “sensing” hereinafter may refer to the estimation of one or more spatial characteristics, (e.g., the absolute and / or relative position; 3D orientation; speed; and / or these characteristics of one or multiple objects not wirelessly connected to the system under consideration). In some example wireless systems, sensing may be considered part of the communication framework, (e.g., when considering integrated sensing and communications).

[0090] There may be at least three sensing modes commonly established. These sensing modes may depend on the relative positions of the transmitter and / or the receiver (or receivers) with respect to the object to be sensed.

[0091] FIG. 2 depicts an example diagram of monostatic sensing performed by a TRP. Monostatic sensing may refer to a scenario where the transmitter and / or receiver entities may be co-located for estimation of one or more of an object’s position, velocity,and / or orientation. Monostatic sensing may be performed by a base station (BS) (e.g., also known as a TRP) 210 and / or by a WTRU. Sensing may be applied to detect one and / or multiple objects 220.

[0092] FIG. 3 depicts an example diagram of bistatic sensing involving a TRP 310 and a WTRU 320. Bistatic sensing may refer to a scenario where the transmitter and / or receiver entities may not be co-located for sensing, (e.g., a TRP 310 acting as transmitter and / or a WTRU 320 as receiver, or vice versa).

[0093] FIG. 4 depicts an example diagram of multistatic sensing involving a TRP 410 and multiple WTRUs 420a, 420b, 420c. Multistatic sensing may refer to a scenario where multiple receiving entities aim to sense one or multiple objects with the aid of a transmitting entity not co-located with them.

[0094] Monostatic sensing may require full duplex capabilities at the sensing entity (WTRU and / or TRP), (e.g., the ability to simultaneously transmit a sensing signal and detect the reflections from the environment). Additionally or alternatively, monostatic sensing may be realized in half duplex mode. In half-duplex mode, the WTRU may perform detection over a receive window that starts when transmission completes, (e.g., using detection techniques not based on Discrete Fourier Transforms (DFTs) that exploit only part of the reflected signals). Bistatic and / or multistatic sensing may not need full duplex as the transmitting and / or receiving entities are different in that case.

[0095] Sensing schemes may also distinguish between active and passive sensing.Active or passive sensing may depend on whether sensing involves transmission of an a priori known signal and subsequent detection of reflected signals (in the active case), or only detection of reflected signals (in the passive case). Methods and / or procedures described hereinafter may generally refer to the active sensing case. However, methods and / or procedures may also apply to passive sensing without loss of generality.

[0096] FIG. 5 depicts an example of CIR peaks produced by sea clutter. In radar terminology, the term “clutter” may denote any object and / or set of objects whose presence is not intended to be detected but produces undesired reflected components at the sensing entity. The presence of clutter may hinder the ability to identify sensing targets. The term “clutter” may comprise either surface clutter (e.g., ground, sea, and / or land masses, etc.), volume clutter (e.g., rain, snow, and / or chaff, etc.), and / or pointclutter e.g., birds, insects, buildings, and / or windmills, etc.). Clutter may be fluctuating or non-fluctuating depending on its variations in time. In cellular environments, clutter produced by relatively large objects e.g., cars, pedestrians, urban furniture, etc.), may be more severe than other traditional clutter sources in free space (e.g., ground, birds, and / or chaff) due to their relatively likely presence in urban environments. Clutter echoes may impair the ability of the receiver to detect targets which calls for methods to discriminate intended scatterers from clutter.

[0097] Sensing may involve some form of beam scanning procedure by the transmitter entity. Sweeping beams may be generated to cover the targeted area in the environment, (e.g., following a sequential order). A receiver may capture the beams’ reflections. In bistatic and / or multistatic sensing, a measurement entity (e.g., a WTRU), may detect one or multiple signal copies reflected by the environment from one or multiple sensing beams. The measurement entity may then perform measurements, (e.g., of delay, power, angle of arrival (AoA), etc.) to differentiate the scatterers from the eventual clutter produced by undesired sources.

[0098] Without limiting the descriptions herein, a bistatic and / or multistatic scenario may comprise one or more TRPs as transmitting entities for sensing and / or one or multiple WTRUs as receivers. The receivers may perform sensing measurements and / or report them back to the network. Other similar bistatic scenarios may be also valid without departure from the ideas disclosed herein (e.g., involving two or more WTRUs, two or more BSs, and / or a transmitting WTRU and a receiving BS).

[0099] The presence of clutter may hinder the ability to identify sensing targets. Properly discriminating intended scatterers from clutter may be an important pre-requisite to avoid wasting unnecessary resources for sensing.

[0100] Illuminating a scatterer with sensing signals may lead to the appearance of secondary reflections caused by other scatterers nearby. These additional reflections may be beneficial to further sense scatterers in the environment in addition to the intended target. However, these additional reflections may also impair the ability to discriminate intended objects from clutter if their ToA and / or AoA are too close to those from the intended scatterers. Moreover, locating scatterers by means of secondaryreflections may require prior knowledge of the emitter that acts as a source for that scatterer, whether it is a transmitting entity and / or a previously identified scatterer.

[0101] As further provided herein, the problems being solved include, but are not limited to: how the WTRU may discriminate and / or report clutter sources and / or intended scatterers in bistatic and / or multistatic sensing. Additional problems being solved may include how the WTRU may identify the emitter source of the signals that impinge on the identified scatterers, and / or discriminate direct reflections from secondary reflections during sensing.

[0102] As depicted in FIG. 11 , described below, a WTRU capable of receiving reference signals for sensing from one or more TRPs may perform one or more of the following actions: the WTRU may signal its capability to detect and / or report scatterers and / or clutter information for sensing, (e.g., in a WTRU capabilities message sent upon initial access and / or registration, and / or upon network request).

[0103] Moreover, the WTRU may receive configuration information on scatterers and / or clutter detection and / or reporting via, e.g., a radio resource control (RRC) configuration, downlink control information (DCI), or medium access control (MAC) control element (MAC CE), containing one or more of sensing thresholds, RS resources, spatial relationships between antenna ports, positioning information, sensing measurement types, triggering conditions, a priori known clutter sources, and / or contents and / or periodicity of the reports, etc.

[0104] The WTRU may obtain CIR responses at the available RS resources and / or antenna ports by, e.g., removing the known RS values and / or computing time-domain responses from the channel frequency responses over a preconfigured time and / or frequency region.

[0105] The WTRU may evaluate triggering conditions. If the triggering conditions are fulfilled, the WTRU may group CIR responses in CIR resource sets according to one or more of the following: the WTRU may identify CIR peaks whose powers or SNRs exceed configured thresholds, the WTRU may measure the CIR peaks’ AoAs and / or checks a first set of CIR peaks at antenna ports quasi co-located (QCL’d) in the same TRP and / or beam whose AoAs may be similar within a configured tolerance. If so, theWTRU may create a new CIR resource set comprising the TRP and / or antenna ports that may be further grouped in an antenna port group.

[0106] If the AoAs of a second set of CIR peaks from antenna ports QCL’d in a different TRP and / or beam may be similar to those in the first set e.g., within the configured AoA tolerance), the WTRU may add a new antenna port group to the CIR resource set containing such TRP and / or antenna ports. The WTRU may repeat the above until all CIR peaks are associated with at least one CIR resource set.

[0107] For each CIR resource set, the WTRU may characterizes scatterers and / or clutter for all antenna port groups by means of one or more of: compare sensing measurements (e.g., ToA, TDoA, AoA, radar cross-section (RCS), and / or reference signal carrier phase (RSCP), etc.) with the information contained in the map of a priori known clutter sources. If the comparison is successful for one or more CIR peaks, the WTRU may assign clutter identifiers, (e.g., a label and / or an ID from a range of allowed values), and / or record its characteristics.

[0108] The WTRU may find a third set of CIR peaks not corresponding to clutter and / or any LOS component whose absolute and / or relative powers and / or SNRs exceed a configured minimum and / or whose AoAs and / or ToAs are similar (e.g., within their configured tolerances) for the antenna ports of a given antenna port group. For each CIR peak in such set, a single value of AoA and / or ToA may be taken as a representative for that antenna port group.

[0109] The WTRU may check if a fourth set of CIR peaks exists in a different antenna port group having similar AoAs and / or inter-arrival times as in the third set of CIR peaks (e.g., within the configured AoA and / or ToA tolerances) and / or whose representative ToAs may be shifted by a common delay difference ATjwith respect to them.

[0110] In such circumstances, the WTRU may assign a single scatterer ID (e.g., an integer ) according to a pre-defined rule, a label, etc.) to the earliest CIR peak in said third and / or fourth sets of CIR peaks. The WTRU may then consider the TRPs of the corresponding antenna port groups as their emitter sources. The WTRU may consider any second, third, etc. peaks in the third and / or the fourth sets of CIR peaks as secondary reflections from scatterer j, which is the common emitter source for those sets of peaks. In some solutions, the WTRU may assign the peaks with suitablescatterer IDs. The WTRU may record Aijas a relative delay difference between the antenna port groups characteristic scatterer j that acts as the common emitter source. Otherwise, the WTRU may assign different scatterer IDs to each of the identified CIR peaks and / or label their emitter sources as unknown, (e.g., via a label ‘empty’, ‘blank’, etc.)

[0111] The WTRU may perform additional sensing measurements on CIR peaks that are not secondary reflections, (e.g., for object identification and / or estimation of their location and / or speed).

[0112] The WTRU may send a scatterers and / or clutter report (e.g., by means of an RRC control message, uplink control information (UCI) signaling, and / or MAC CE). The report may contain, for each CIR resource set, one or more of its antenna port groups, time stamp, clutter information (e.g., clutter IDs, measurements, accuracies, clutter type, and / or confidence levels, etc.), scatterer information (e.g., scatterer IDs, emitter sources, measurements, accuracies, relative delay differences between antenna port groups, location, speed, and / or object type, etc.).

[0113] The WTRU may check triggering conditions for scatterers and / or clutter identification update. If met, the WTRU may perform new sensing measurements and / or transmit an updated report with the time stamp and / or the characteristics of any newly identified and / or updated clutter sources and / or scatterers.

[0114] The WTRU may check triggering conditions for scatterers and / or clutter identification termination. If met, the WTRU may terminate the procedure and / or send a control signaling to the network containing a termination indication (e.g., via RRC, UCI signaling, and / or MAC CE, etc.)

[0115] As disclosed herein a “UE”, “sensing receiver” and / o “WTRU” may be used interchangeably. A “sensing transmitter” may refer to any entity transmitting sensing signals. It may be used interchangeably with the terms “TRP”, “gNB” and / or “BS” in a non-limiting way. The terms “scatterer”, “intended scatterer”, “object”, “sensing object”, “target” and / or “sensing target” may be used interchangeably to refer to an object whose characteristics may be intended to be sensed and / or not wirelessly connected to the system under consideration. The terms “clutter”, “clutter source”, “unintended target” and / or “unintended object” may be used to describe an object, or set of objects, whosepresence leads to undesired reflected and / or scattered signals not intended to be sensed (e.g., from ground, sea, buildings, birds, cars, and / or parts of urban furniture, etc.). The term “MPC” may be used interchangeably with “multipath component.” The term “ToA” may be used interchangeably with time of arrival and / or denotes the time of a given MPC measured with respect to, e.g., the start of the subframe. The term “CIR peak” or “power delay profile (PDP) peak” may be used interchangeably to denote the presence of a correlation above a threshold between the received signal and / or the transmitted sensing signal for a ToA that characterizes the multipath delay. The terms “environment impulse response”, “channel impulse response”, “sensing channel state”, and / or “sensing CSI” may be used interchangeably to refer to any channel state information characterizing the radio environment being sensed. The term “secondary reflection” may refer to one or more reflections caused by an object after further receiving echoes from another object, whether intended or non-intended to be sensed. One scatterer may lead to one or multiple secondary reflections by surrounding objects.

[0116] The terms “QCL” and “quasi co-located” may be used interchangeably to refer to antenna ports that share certain macroscopic channel characteristics (e.g., their average delay, Doppler spread, etc.). In some cases, a QCL relationship between antenna ports may be established such that their corresponding beam and / or TRP may be considered the same by the WTRU. This may be denoted as a set of antenna ports that are QCL’d in the same beam and / or TRP. A set of antenna ports for sensing that are QCL’d in the same sensing beam and / or TRP may be denoted as an antenna port group.

[0117] It may be assumed herein that a cellular scenario may be considered where one or multiple TRPs aimed to sense the environment with the help of one or multiple WTRUs perform sensing measurements. The sensing measurements may derive spatial information about the surrounding objects, (e.g., their location, speed, and / or orientation, etc.) as determined by the system and / or the application.

[0118] FIG. 6 depicts an example of bistatic sensing scenario with two sensing transmitters 610a, 610b, one sensing receiver 620, three scatterers 630a, 630b, 630c, and three clutter sources 640a, 640b, 640c. In a bistatic sensing scenario shown in FIG. 6, one or more sensing transmitters 610a, 610b may send reference signalscaptured by a sensing receiver 620 with the goal of sensing one or more targets in the environment (e.g., to determine their location, velocity, and / or object type (e.g., a pedestrian, car, etc.)). It may be assumed herein that the sensing transmitters 610a, 610b need not be time-synchronized for sensing and / or a time mismatch may exist between sensing transmissions from different entities.

[0119] A sensing transmitter (e.g., a TRP) 610a, 610b may comprise any number of transmit-receive antennas (e.g., in a massive multiple input - multiple output (M-MIMO) configuration), with up to N antenna ports for the transmission of sensing signals. WTRUs may be equipped with one or multiple receive antennas.

[0120] A suitable RS may already exist for sensing measurements, either in the form of an existing signal re-purposed for sensing (e.g., the downlink (DL) positioning reference signal (PRS) or the uplink (UL) sounding reference signal for positioning (SRSp) in 5G NR, and / or a dedicated sensing signal). Descriptions herein do not make any assumptions regarding the type or structure of the RS structure used for sensing measurements. Similarly, it may be assumed that a suitable RS already exists for sensing CSI acquisition, (e.g., CSI-RS, SSB, and / or any other signal). In addition, stationarity of the channel is assumed at each sensing transmitter 610a, 610b. In other words, individual antenna elements may experience similar macroscopic channel characteristics (e.g., ToAs and / or AoAs, etc.) across the array.

[0121] Descriptions hereinafter apply to any signal waveform susceptible of frequencydomain analysis. For simplicity, an orthogonal frequency divisional multiplexing (OFDM)-like waveform, e.g., cyclic prefix (CP)-OFDM and / or DFT-s-OFDM, may be used in the descriptions comprising discrete samples in the time or frequency domain, but other waveforms may be similarly used.

[0122] The proposed methods may help optimize bistatic and / or multistatic sensing due to the following benefits, including, but not limited to: detect and / or report clutter sources to avoid wasting processing resources on the identification of unintended targets; identify scatterers and / or associate them to groups of antenna ports for bistatic sensing; discriminate secondary reflections and / or identify their source scatterers; provide additional measurements on the identified scatterers to potentially enhance their detection (e.g., via beamforming and / or precoding).

[0123] Methods and / or procedures may be described hereinafter for the identification, characterization, and / or reporting of scatterers and / or clutter by the WTRU for bistatic and / or multistatic sensing measurements.

[0124] FIG. 7 illustrates a set of scatterers and / or clutter sources illuminated by TRP ki and TRP k2 that yield CIR responses as shown in FIG. 7. Without loss of generality, CIR peaks from both TRPs caused by scatterer 1 710a may be characterized by the angles of arrival AoA1 720a, AoA2 720b, and / or AoA6 720c and / or a delay equal to T1740. Scatterer 2 710b and / or scatterer 3 710c in FIG. 7 are illuminated by TRP k2, but not by TRP ki (through reflection from scatterer 1 710a).

[0125] In the descriptions that follow, a CIR peak and / or PDP peak may refer to a CIR and / or PDP value above a pre-configured threshold and / or a correlation value between the received signal and / or the transmitted sensing signal above a threshold.

[0126] A WTRU may receive and / or decode a first network request (e.g., received through RRC signalling) to provide capability information. The WTRU may receive and / or decode this first network request following the random-access procedure. The WTRU may prepare a capability information message including information related to sensing capabilities such as scatterers and / or clutter identification.

[0127] The information contained in the WTRU capabilities message may include one or more of the following: sensing processing capabilities (e.g., inverse frequency transform capabilities and / or maximum number of samples, etc.); sensing frequency ranges; sensing bandwidth; sensing modes (e.g., monostatic and / or bistatic, etc.); sensing priorities; sensing spatial resolution; sensing time resolution; support of AoA determination and / or related AoA resolution; sensing doppler resolution; reflectivity sensitivity (e.g., the minimum power, SNR, and / pr absolute amplitude, etc. for the reflections to be detectable by the WTRU); support of carrier phase measurements and / or related phase resolution; and / or support of half-duplex and / or full-duplex for monostatic sensing, and / or related parameters (e.g., frequency range, maximum allowed transmit power for sensing, etc.).

[0128] The WTRU may send the WTRU capability information message through RRC signaling (e.g., over the PUSCH). The network may use the WTRU capability information to optimize its configuration and / or resource allocation for sensing.

[0129] The WTRU may detect and / or report scatterers and / or clutter from, e.g., a control or data channel via RRC configuration, DCI information, and / or MAC CE signaling, etc. by means of one or more of the following information received: threshold amplitude, power, SNR, and / or a CIR peak to be further considered for sensing.

[0130] Information received may further include, but not be limited to: the RA resources for CIR estimation (e.g., CSI-RS, PRS, etc.) for all the available antenna ports from the one or more sensing TRPs, e.g., time / frequency allocation, bandwidth, symbol and / or comb offsets, periodicity, etc.

[0131] Assistance information to perform inverse frequency transformations for obtaining CIR responses, (e.g., frequency range, bandwidth, frequency layer identifier (e.g., PFL-ID), bandwidth part (e.g., BWP-ID), and / or number of FFT samples, etc.).

[0132] Spatial relationships between antenna ports for sensing, including information about the antenna ports co-located in a same TRP and / or beam, (e.g., in the form of configured TCI states with associated QCL characteristics).

[0133] Positioning information (e.g., expressed as the ToA of the LOS component for each sensing TRP, AoAs, coordinates of WTRU and sensing TRPs, and / or LOS likelihoods, etc.).

[0134] Measurements to perform (e.g., ToA, TDoA, AoA, absolute and / or relative reference signal received power to path (RSRPP), RSCP, doppler spectrum, and / or RCS, etc.).

[0135] Information received may further include, but not be limited to: triggering conditions for scatterers and / or clutter identification. The triggering conditions may be expressed as one or more of the following: the CIRs of at least K antenna ports (K<N), and / or their average PDP responses, may fulfil any of the following conditions: number of MPCs above a first threshold; characteristics of the MPCs similar to those of clutter sources (e.g., their spatial correlation, polarization, etc.); difference between the obtained RCS and / or one or more RCS of clutter sources (e.g., sea, and / or ground, etc.) below a second threshold; the difference between a measured PDF and / or the PDF of a clutter source (e.g., ‘Gaussian’, ‘Log-Normal’, ‘Weibull’, and / pr ‘Rayleigh’, etc.) below a third threshold; the difference between a measured Doppler spectrum and / or the Doppler spectrum of a clutter source below a fourth threshold; the presence of oneor more scatterers showing, (e.g., a delay dispersion above a fifth threshold, a width of the CIR peaks above a sixth threshold, etc., that may be characteristic of diffuse reflection); and / or a network request, (e.g., over a configured time window).

[0136] The information received may further include, but not be limited to: triggering conditions for scatterers and / or clutter identification update (e.g., a change in the CIR characteristics, a maximum WTRU velocity or change in the position, an absolute and / or relative duration, etc.); and / or triggering conditions for scatterers and / or clutter identification termination, (e.g., a minimum number of available RS resources, MPCs, scatterers, etc. below a threshold, an absolute and / or relative duration, etc.).

[0137] Map of a priori known clutter sources, e.g., expressed as a list of CIR responses, ToAs, absolute and / or relative powers, AoAs, distances, location, etc. may be associated with CIR resource sets. Thresholds for scatterers identification (e.g., minimum absolute and / or relative powers or SNRs for the CIR peaks in the average PDP response of at least K antenna ports (K<N), tolerance of AoA, ToA, etc. measurements between antenna ports, etc.) Information to report about the scatterers, (e.g., one or more of ToA (absolute and / or relative to the LOS component), TDoA, AoA, RSRPP, RSCP, RCS, doppler spectrum, coordinates, speed, and / or type of object, etc.) Information to report about clutter sources (e.g., a statistical distribution that matches any of the AoA, ToA, TDoA, RSRPP, RSCP, etc.); a moment order for a defined probability distribution; a range of values for the measured quantities; a difference between measured data and / or a clutter distribution via, e.g., Kullback-Leibler divergence and / or a chi-square test, etc. Periodicity of the reports (e.g., in number of slots and / or frames, etc.) between reporting occasions for periodic and / or semi-periodic cases, and / or as an aperiodic indication.

[0138] The WTRU may receive a re-configuration message from the network containing updated configuration parameters for scatterers and / or clutter detection (e.g., from a control or data channel via RRC configuration, DCI information, and / or MAC CE signaling, etc.). This message may contain part or all of the above information, and its reception may override part and / or all of a configuration previously received by the WTRU.

[0139] The WTRU may receive a first set of RSs for sensing per the sensing configuration. The RS may come in the form of, e.g., a SSB, CSI-RS, PRS, and / or a dedicated RS for sensing, etc. The network may configure the WTRU to measure at least one of the ToA, TDoA, AoA, absolute and / or relative RSRPP, RSCP, doppler spectrum, and / or RCS, etc. with the associated time from the resources. The WTRU may perform the configured measurement in the allocated measurement time window indicated to the WTRU.

[0140] The time window configuration may consist of at least one of the following: start and / or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, and / or relative time with respect to a reference point); duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, and / or seconds); and / or periodicity of the window (e.g., in terms of number of symbols, slots, frames, subframes, and / or seconds).

[0141] The WTRU may receive multiple RSs from one or multiple configured antenna ports for sensing (e.g. from different TRPs and / or single TRP). In that case, the WTRU may perform multiple configured (e.g., pre-configured) measurements at the different channel responses obtained from the available TRPs and / or antenna ports for sensing. The WTRU configured (e.g., pre-configured) measurements may include obtaining: the channel frequency responses at the configured RS resources, (e.g., by removing the known values of the RS complex symbols and / or performing interpolation of the resulting responses over the desired frequency region).

[0142] The WTRU configured (e.g., pre-configured) measurements may further include obtaining the corresponding time-domain CIR responses, (e.g., by performing inverse frequency transformations, such as the Discrete Fourier Transforms, to the obtained frequency responses). The WTRU may obtain the PDP responses by computing the absolute square magnitude of the CIR responses.

[0143] The WTRU configured (e.g., pre-configured) measurements may keep CIR and / or PDP peaks whose powers or SNRs exceed the minimum configured threshold, and / or whose peak correlation value between the received signal and / or the transmitted sensing signal is above a threshold. The WTRU may discard all others.

[0144] The WTRU may keep the CIR and / or PDP peaks received within a preconfigured ToA and / or delay window. The WTRU may discard all the others. The WTRU may compare the CIR and / or PDP responses against a preconfigured CIR and / or PDP response expressed as a function of time. The WTRU may select the CIR peaks such that the difference between the probability density function (PDF) of the measured CIR and / or PDP response, and / or one or more preconfigured CIR and / or PDP responses, are below a preconfigured threshold.

[0145] The WTRU may perform the inverse frequency transformation based on its capability. The WTRU may receive at least one of the following forms of assistance information for performing the inverse frequency transformation: in a first such example, the network may indicate the RS carrier frequency range where the WTRU may perform the inverse frequency transformation. The network may indicate to the WTRU in terms of: start frequency, stop frequency (e.g., in terms of Hz, number of REs, and / or number of RBs, etc.); frequency offset with respect to an indicated reference frequency (e.g., ARFCN); frequency bandwidth (e.g., in terms of Hz, number of RBs, and / or number of REs, etc.); a frequency layer identifier (e.g., PFL-ID); a subset of the carrier bandwidth to be used for sensing (e.g., a BWP-ID). The WTRU may indicate the number of samples for the frequency transformation (e.g., number of samples for inverse-FFT).

[0146] The WTRU may group CIR responses into CIR resource sets. The WTRU may check the triggering conditions for scatterers and / or clutter identification. If the triggering conditions are fulfilled, the WTRU may perform an association between antenna port groups and / or scatterers to determine which scatterers are illuminated by which combinations of antenna ports. A CIR resource set may hereinafter denote an association between a set of (one or more) scatterers and / or a set of (one or more) antenna port groups that illuminate them. An antenna port group may belong to one or more CIR resource sets.

[0147] To group CIR responses into CIR resource sets, the WTRU may perform one or more of the following steps: first, the WTRU may identify one or more CIR peaks in the obtained CIR responses whose absolute and / or relative powers, or SNRs, are above the configured thresholds for scatterer identification.

[0148] For each of the identified CIR peaks at the obtained CIR responses, the WTRU may measure the AoAs of the CIR peaks and / or check the presence of a first set of CIR peaks at antenna ports that are QCL’d in the same TRP and / or beam whose AoA values are similar within the configured AoA tolerance. If identified, the WTRU may create a new CIR resource set comprising the corresponding antenna ports and / or TRP which are further grouped in an antenna port group. The CIR resource group may be assigned an integer in a set of predefined values, a label, and / or an index, etc. The WTRU may characterize the antenna port group by a suitable identifier, a label, etc. and / or assign the antenna port group to the CIR resource set.

[0149] The WTRU may check if the measured AoAs of a second set of CIR peaks corresponding to antenna ports that are QCL’d in a different TRP and beam are similar to those in the first set (within the configured AoA tolerance). In such case, the WTRU may add a new antenna port group containing the corresponding TRP and antenna ports to the CIR resource set. The WTRU may repeat the above process until all the identified CIR peaks in the CIR responses are associated with at least one CIR resource set.

[0150] After the above process is complete, the WTRU may obtain one or more CIR resource sets each characterized by: an unambiguous identifier (e.g., a label, and / or an index, etc.); and / or one or more antenna port groups, each containing a TRP identifier and a set of one or more antenna ports that are co-located in that same TRP and / or beam. An integer, a label, and / or an index in a table, etc. may identify an antenna port group. The WTRU may further employ the resulting CIR resource sets to characterize scatterers and / or clutter and / or to identify the emitter sources for the secondary reflections.

[0151] The WTRU may characterize clutter sources and / or scatterers by means of one or more of the following steps for each identified CIR resource set: first, the WTRU may perform sensing measurements of one or more of ToA, TDoA, AoA, RCS, RSCP, doppler spectrum, power, and / or SNR, etc. per multipath on the obtained CIR and / or PDP responses. The WTRU may compare them with the information contained in the provided map of a-priori known clutter sources. The WTRU may also compare themwith the triggering conditions related to clutter identification (e.g., their statistical distribution of RCS, ToA, AoA, and / or doppler spectrum, etc.)

[0152] The confidence level of an estimated clutter distribution may be obtained via, e.g., Kullback-Leibler divergence, and / or a chi-square test, etc., to assess the presence of clutter.

[0153] The presence of multiple sensing antenna ports may be leveraged to enhance sensing measurements. In some solutions, PDP responses in an antenna port group may be aggregated and / or averaged to compensate an otherwise poorly resolvable ToA and / or AoA because of a destructive interference. PDP responses may also be aggregated and / or averaged to apply a robust covariance estimation in multivariate analysis to detect clutter. Sensing SNR may improve with the number N of antenna ports when the sensing RS follows a frequency-staggered and / or non-overlapping pattern that allows the available power for sensing to increase with N.

[0154] Based on the comparison, the WTRU may detect the presence of one or more CIR peaks caused by clutter and / or assign them a clutter identifier (e.g., a label, and / or an ID from a range of allowed values, etc.) together with its sensing measurements. The WTRU may identify a third set of peaks in the CIR responses of the CIR resource set fulfilling one or more of the following conditions: their absolute and / or relative powers and / or SNRs may exceed the configured minimum threshold for scatterers identification. The WTRU may identify whether the third set of peaks do not correspond to any LOS component and do not meet the conditions for clutter identification. The WTRU may distinguish LOS components with the aid of the positioning information in the configuration step (containing, e.g., the ToA, and / or AoA, etc. of the LOS component from each TRP or the coordinates of the TRP). The WTRU may identify whether third set of peaks by their angles of arrival e.g., AoA1 , AoA2, ... ) and / or ToAs e.g., TI , T2, ... ) measured at the antenna ports of a given antenna port group, and whether they are similar within their configured tolerances. A single value of AoA and / or ToA may be taken as representative of each peak for that antenna port group (e.g., their arithmetic and / or geometric mean).

[0155] The WTRU may identify a fourth set of CIR peaks in a different antenna port group having similar AoAs and / or inter-arrival times as in said third set of CIR peaks (within the configured AoA and / or ToA tolerances).

[0156] Referring again to FIG. 7, which depicts an example of CIR peaks in a two-TRP scenario received from antenna port groups ki 750a and k2 750b showing the contributions from scatterers 1 710a, 2 710b, and 3 710c and clutter sources 1 760a, 2 760b, and 3 760c. Encircled peaks represent the contributions from scatterer 1 710a seen by the antenna port groups ki 750a and k2 750b including its secondary reflections 770a, 770b. As seen in FIG. 7, the fourth set of CIR peaks may have representative ToAs shifted by a common delay difference Ad with respect to those representative ToAs.

[0157] If the identification process is successful, the WTRU may assign a single scatterer ID (e.g., an integer j according to a pre-defined rule, and / or a label, etc.) to the earliest CIR peaks in said third and / or fourth sets of CIR peaks. The WTRU may consider that the emitter sources of the identified scatterer j are the TRPs of the corresponding antenna port groups. FIG. 8 depicts an example of CIR peaks in a single- TRP scenario showing an intended scatterer j 810a.

[0158] For any second, third, etc. CIR peaks in the third and / or the fourth sets of CIR peaks, the WTRU may: label those CIR peaks as secondary reflections from scatterer j 810a, which is the common emitter source for those sets of peaks, and / or record their relative delay difference Ad between antenna port groups that is characteristic of the scatterer j 810a acting as the emitter source. The Ad may be equal to the difference in propagation times between the scatterer and / or the TRPs in the antenna port groups, including any eventual time mismatch between TRP transmissions. The WTRU may assign additional scatterer identifiers to the secondary reflections.

[0159] Otherwise, if the identification process is not successful, the WTRU may assign different scatterer IDs to each of the CIR peaks identified. The WTRU may label its corresponding emitter sources as unknown (e.g., using an ‘empty’ or ‘blank’ label, and / or a special identifier). The WTRU may repeat the above steps for all CIR resource sets and / or antenna port groups until all CIR peaks are classified and their properties characterized.

[0160] The WTRU may perform additional sensing measurements on CIR peaks which are not secondary reflections. These additional sensing measurements may identify and / or estimate the location and / or speed of the corresponding objects if configured and / or determined to do so.

[0161] As a result of these steps, the WTRU may obtain environmental information characterizing the scatterers and / or clutter as sensed from the different TRPs and / or antenna port groups. This information may enrich the sensing measurements reported to the network.

[0162] Having multiple TRPs may increase the chances of correctly characterizing the scatterers and / or clutter surrounding the WTRU. In some cases, scatterers not illuminated by TRPs in a given CIR resource set may be illuminated by other TRPs in a different CIR resource set. The WTRU may thus try to search all possible CIR resource sets to identify as many scatterers as possible. In addition, having multiple TRPs allow distinguishing secondary reflections and / or identify their emitter sources.

[0163] A single TRP may not be sufficient to discriminate between scatterers and / or their secondary reflections (e.g., as depicted in FIG. 6). If no sensing Tx entity k2 exists, then the WTRU may have no means to determine whether CIR peaks at ToA 12 820b and / or AoA2 830 in FIG. 8 (corresponding to scatterer 2 810b) are caused by a direct reflection with TRP ki as the emitter source and / or a secondary reflection with scatterer 1 as the emitter source. In such cases, the WTRU may only try to determine the location of the scatterer corresponding to the first CIR peak after the LOS path (e.g., at ToA n 820a), as it will most likely correspond to a direct reflection. A direct reflect from a scatterer may not occur in anomalous circumstances (e.g., a situation with full LOS blockage and / or the signal reflecting on multiple cascaded scatterers before reaching the WTRU). Other non-cellular means may detect such anomalous cases e.g., cameras and / or sensors, etc.), and / or further precluded from sensing.

[0164] The WTRU may send a report on scatterers and / or clutter information for each identified CIR resource set. The information may include several types of information following in compressed mode, uncompressed mode, and / or as entries in a table as seen in FIG. 9. FIG. 9 depicts an illustration of the contents of a scatterers and / or clutter identification report.

[0165] Information on the report may include, but not be limited to, antenna port groups 920 comprised in the CIR resource set 910a, 910b; time stamp of the measurements 930 (e.g., in absolute and / or relative time, or as a number of slots and / or frames, etc.) relative to a known reference.

[0166] The information on the report may further include, but not be limited to: identified clutter identifiers (IDs) 940a, 940b and for each of the identified clutter IDs, 940a, 940b one or more of the following: sensing measurements, (e.g., given as a statistical distribution of RCS, ToA, TDoA, AoA, RSRPP, doppler spectrum, and / or a range of measured values, etc.); confidence level of an estimated clutter distribution e.g., obtained as a Kullback-Leibler divergence and / or a chi-square test, etc.); measurement accuracies (e.g., given as the variance or uncertainty in the corresponding magnitudes); estimated clutter type (e.g., a label of type ‘sea’, ‘ground’, and / or ‘foliage’, etc.) with the corresponding confidence level.

[0167] The information on the report may further include, but not be limited to: identified scatterer IDs 950a, 950b and for each of the identified scatterer IDs 950a, 950b, one or more of the following: emitter source for that scatterer, (e.g., whether it is a TRPs, or another identified scatterer, or unknown); sensing measurements (e.g., ToA, TDoA, AoA, absolute and / or relative RSRPP, RSCP, MPC number in the PDP, doppler spectrum, and / pr RCS, etc.). If multiple antenna ports exist, representative ToA and / or AoA values may be provided, e.g., by averaging across the antenna ports in the antenna port group. If multiple ToAs from different antenna port groups may characterize the scatterer, the WTRU may additionally provide the relative delay differences T! between the corresponding CIR peaks in the different antenna port groups. ToAs may be reported relative to the ToA of the corresponding LOS component (if present), or in addition to it. AoA values may be reported with respect to a WTRU orientation vector (e.g., a vector perpendicular to the receive antenna panel and / or any other predefined WTRU surface with reportable coordinates), and / or may be expressed as, e.g., indexes in a table of predefined directions.

[0168] Moreover, for each of the identified scatterer IDs 950a, 950b, the report may further include measurement accuracies (e.g., given as the variance or uncertainty in the corresponding magnitudes).

[0169] The WTRU may obtain any of the estimated location (e.g., in latitude / longitude, or as coordinates in a suitable reference system, etc.), its speed, and object type (e.g., a label of type ‘car’, ‘pedestrian’, and / or ‘bicycle’, etc.) with the corresponding confidence levels.

[0170] The report may further include any additional information about CIR peaks that may help in their detection, e.g., their amplitudes, phases, etc. in absolute and / or relative form, and / or as indexes in a codebook.

[0171] The report may be transmitted in an uplink control and / or data channel e.g., a physical uplink control channel (PUCCH) and / or physical uplink shared channel (PUSCH)), and may be conveyed by, e.g., an RRC control message, UCI signaling, or MAC CE, etc.

[0172] The WTRU may detect and / or report scatterers and / or clutter over one or more measurement occasions. The WTRU may determine that the identified scatterers and / or clutter in the report are outdated, or their corresponding measurements invalidated.

[0173] The WTRU may base its determination on one or more of the following triggering conditions for scatterers and / or clutter identification update, as provided by the network as part of the WTRU configuration: a change in the number of MPCs, ToAs, TDoAs, AoAs, RSCP, doppler shifts and / or spreads, and / or amplitudes and / or phases of the CIR peaks, etc., from one or more antenna ports above a threshold; a change in any of the characteristics of the identified clutter sources (e.g., their clutter types, their probability distributions, etc.); a WTRU re-configuration message containing updated configuration parameters for detection and reporting of scatterers and clutter, and / or an updated map of known clutter sources; a change in the number of scatterers whose absolute and / or relative power, and / or SNR, is above the configured threshold for scatterers identification; a change above a threshold in the relative delay difference between sets of CIR peaks in different antenna port groups containing secondary reflections from a given scatterer; a change in the detected RS resources, (e.g., the birth or death of one or more RS at their configured time-frequency locations); an absolute and / or relative change in the WTRU coordinates above a threshold; a WTRU velocity above a threshold, and / or within a preconfigured range; a measured velocity of any of the identified scatterers above a threshold, and / or within a preconfigured range; atime elapsed since the last reporting of scatterers and / or clutter information exceeding an absolute and / or relative duration, (e.g., a configured periodicity); a network request.

[0174] Based on any of the above triggering conditions, the WTRU may obtain updated CIR responses and / or CIR resource sets 1010a, 1010b; perform new sensing measurements; characterize scatterers and / or clutter. FIG. 10 depicts an illustration of the contents of a scatterers and clutter identification update.

[0175] The WTRU may also transmit an updated report in an uplink control and / or data channel containing one of more of the following, e.g., through an RRC control message, UCI signaling, and / or MAC CE, etc. As seen in FIG. 10: the updated resource sets 1010a, 1010b may include a time stamp 1020 of the updated measurements (e.g., in absolute and / or relative time, and / or as a number of slots, and / or frames, etc. relative to a known reference); and / or clutter IDs 1030a, 1030b corresponding to newly identified and / or updated clutter sources.

[0176] For each of the identified and / or updated clutter IDs1030a, 1030b, the WTRU may report one or more of the following: sensing measurements (e.g., given as a statistical distribution of RCS, ToA, AoA, and / or doppler spectrum, or a range of measured values); confidence level of an estimated clutter distribution, (e.g., obtained as a Kullback-Leibler divergence, and / or chi-square test, etc.); measurement accuracies (e.g., given as the variance or uncertainty in the corresponding magnitudes); estimated clutter type (e.g., a label of type ‘sea’, ‘ground’, and / or ‘foliage’, etc.) with the corresponding confidence level.

[0177] The WTRU may also transmit an updated report scatterer IDs 1040a, 1040b corresponding to newly identified and / or updated scatterers. For each of the identified and / or updated scatterers, the WTRU may report one or more of the following: emitter source for that scatterer (e.g., whether it is a TRP, another identified scatterer, or unknown); sensing measurements (e.g., ToA, TDoA, AoA, absolute and / or relative RSRPP, RSCP, MPC number in the PDP, and / or doppler spectrum, RCS, etc.); measurement accuracies; in some cases, estimated location, speed, object type, and / or confidence levels, etc.; any additional information about CIR peaks for their detection, (e.g., their amplitudes and / or phases, etc. in absolute and / or relative form, and / or as indexes in a codebook).

[0178] FIG. 11 depicts an example flowchart of a wireless transmit / receive unit (WTRU) and TRP actions for scatterers and clutter identification. The WTRU may detect and / or report scatterers and / or clutter over one or more measurement occasions. At 1110, the WTRU may then signal its capabilities of scatterers and / or clutter detection and / or reporting to the available TRPs. At 1120, the WTRU may then receive configuration information from the TRPs. At 1130, the WTRU may receive RSs for CIR estimation, and / or the WTRU may obtain CIR responses and / or evaluate triggering conditions. If triggering conditions are fulfilled, at 1140 the WTRU may group CIR responses in one or more CIR resource sets. At 1150, the WTRU may characterize scatterers and / or clutter for each CIR resource set and / or antenna port groups. At 1160, the WTRU may perform sensing measurements on peaks that are not secondary reflections. At 1170, the WTRU may report scatterers and / or clutter information to the available TRPs. At 1180, the WTRU may perform updated measurements and / or transmit an updated report to the TRPs. At 1190, the WTRU may determine that the identification process may terminate based on triggering conditions for scatterers and / or clutter identification termination, as provided by the network as part of the WTRU configuration, and / or send a control signaling to the network containing a termination indication via, e.g., an uplink control and / or data channel carrying an RRC message, UCI signaling, and / or MAC CE, etc.

[0179] The triggering conditions may include, but not be limited to: the CIRs of at least K’ antenna ports (K’<N), and / or their average PDP responses that do not meet the triggering conditions for scatterers and / or clutter identification; the number of scatterers whose absolute and / or relative power, and / or SNR, exceeds the configured threshold for scatterers identification is below a threshold; a WTRU re-configuration message for detection and / or reporting of scatterers and / or clutter wherein any of the number of antenna ports and / or available RS resources for CIR estimation is below a threshold; an absolute and / or relative change in the WTRU coordinates below a threshold; a WTRU velocity below a threshold and / or outside a preconfigured range; a measured velocity of all the identified scatterers, and / or a subset of them, below a threshold, and / or outside a preconfigured range; a time elapsed since the last reporting of scatterers and / or clutter information exceeding a maximum absolute and / or relative duration; a network request; and / or a low-battery indication at the WTRU.

Claims

CLAIMS1 . A wireless transmit / receive unit (WTRU) comprising: a processor and a memory, the processor and memory configured to: send an indication that the WTRU has the capability to detect and report scatterer and clutter information; receive first configuration information associated with scatterer and clutter information and second configuration information associated with reference signals (RS) resources and antenna ports used to report the scatterer and clutter information, wherein the first configuration information indicates one or more triggering conditions; determine a plurality of channel impulse responses (CIRs) based on the second configuration information; determine to group the CIRs into one or more CIR resource sets based on the one or more triggering conditions; and send a report comprising the scatterer and clutter information associated with the antenna ports for each of the one or more CIR resource sets.

2. The WTRU of claim 1 , wherein the triggering conditions comprise an angle of arrival (AoA) of the CIRs being within a threshold angle or a signal-to-noise ratio (SNR) of a CIR exceeding a threshold SNR.

3. The WTRU of claim 1 , wherein the CIRs of a CIR resource set are characterized by one or more angles of arrival (AoAs) that are within a threshold range of angles of one another.

4. The WTRU of claim 3, wherein the processor is further configured to: determine to group the antenna ports whose AoA values are within a threshold range of one another into an antenna port group; and assign one or more antenna port groups to the CIR resource set.

5. The WTRU of claim 1 , wherein the processor is further configured to: identify an emitter source of secondary reflections based on the one or more CIR resource sets.

6. The WTRU of claim 1 , wherein the scatterer and clutter information comprises, for each CIR resource set, one or more of an indication of antenna port groups associated with the CIR resource set, a time stamp associated with the CIR resource set, a clutter identifier associated with the CIR resource set, or a scatterer identifier associated with the CIR resource set.

7. The WTRU of claim 6, wherein the clutter identifier indicates one or more of measurements associated with the CIRs of the CIR resource set, a measurement accuracy associated with the CIRs of the CIR resource set, a clutter type associated the CIR resource set, or a confidence level associated with the CIR resource set; and wherein the scatterer identifier indicates one or more of emitter sources associated with the CIRs of the CIR resource set, a sensing measurement associated with the CIRs of the CIR resource set, a measurement accuracy associated with the CIRs of the CIR resource set, or a delay difference between antenna port groups associated with the CIR resource set.

8. The WTRU of claim 7, wherein the sensing measurements associated with the CIRs of the CIR resource set comprise one or more of time of arrival (ToA), time difference of arrival (TDoA), angle of arrival (AoA), absolute and / or relative reference signal received power (RSRP), received signal code power, multipath component in the power delay profile (PDP), doppler spectrum, or radar cross-section.

9. The WTRU of claim 1 , wherein the processor is configured to: perform sensing measurements on peaks of the CIRs of the CIR resource sets that are not associated with secondary reflections; and estimate, based on the performed sensing measurements, the location or speed of one or more objects from which the secondary reflections are reflected.

10. The WTRU of claim 1 , wherein the processor is configured to: determine, after sending the report, whether the one more triggering conditions are associated with newly identified or updated scatterer and clutter information; perform sensing measurements based on the triggering conditions being associated with newly identified or updated scatterer and clutter information; determine, based on the performed sensing measurements, newly identified or updated scatter and clutter information; and send an updated report comprising a time stamp and characteristics associated with the newly identified or updated scatterer and clutter information.

11. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: sending an indication that the WTRU has the capability to detect and report scatterer and clutter information; receiving first configuration information associated with scatterer and clutter information and second configuration information associated with reference signals (RS) resources and antenna ports used to report the scatterer and clutter information, wherein the first configuration information indicates one or more triggering conditions; determining a plurality of channel impulse responses (CIRs) based on the second configuration information; determining to group the CIRs into one or more CIR resource sets based on the one or more triggering conditions; and sending a report comprising the scatterer and clutter information associated with the antenna ports for each of the one or more CIR resource sets.

12. The method of claim 11 , wherein the triggering conditions comprise an angle of arrival (AoA) of the CIRs being within a threshold angle or a signal-to-noise ratio (SNR) of a CIR exceeding a threshold SNR.

13. The method of claim 11 , wherein the CIRs of a CIR resource set are characterized by one or more angles of arrival (AoAs) that are within a threshold range of angles of one another.

14. The method of claim 13, further comprising: determining to group the antenna ports whose AoA values are within a threshold range of one another into an antenna port group; and assigning one or more antenna port groups to the CIR resource set.

15. The method of claim 11 , further comprising: identifying an emitter source of secondary reflections based on the one or more CIR resource sets.

16. The method of claim 11 , wherein the scatterer and clutter information comprises, for each CIR resource set, one or more of an indication of antenna port groups associated with the CIR resource set, a time stamp associated with the CIR resource set, a clutter identifier associated with the CIR resource set, or a scatterer identifier associated with the CIR resource set.

17. The method of claim 16, wherein the clutter identifier indicates one or more of measurements associated with the CIRs of the CIR resource set, a measurement accuracy associated with the CIRs of the CIR resource set, a clutter type associated the CIR resource set, or a confidence level associated with the CIR resource set; and wherein the scatterer identifier indicates one or more of emitter sources associated with the CIRs of the CIR resource set, a sensing measurement associated with the CIRs of the CIR resource set, a measurement accuracy associated with the CIRs of the CIR resource set, or a delay difference between antenna port groups associated with the CIR resource set.

18. The method of claim 17, wherein the sensing measurements associated with the CIRs of the CIR resource set comprise one or more of time of arrival (ToA), timedifference of arrival (TDoA), angle of arrival (AoA), absolute and / or relative reference signal received power (RSRP), received signal code power, multipath component in the power delay profile (PDP), doppler spectrum, or radar cross-section.

19. The method of claim 11 , further comprising: performing sensing measurements on peaks of the CIRs of the CIR resource sets that are not associated with secondary reflections; and estimating, based on the performed sensing measurements, the location or speed of one or more objects from which the secondary reflections are reflected.

20. The method of claim 11 , further comprising: determining, after sending the report, whether the one more triggering conditions are associated with newly identified or updated scatterer and clutter information; performing sensing measurements based on the triggering conditions being associated with newly identified or updated scatterer and clutter information; determining, based on the performed sensing measurements, newly identified or updated scatter and clutter information; and sending an updated report comprising a time stamp and characteristics associated with the newly identified or updated scatterer and clutter information.

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