Methods and procedures for bistatic and multistatic sensing

Abstract

The wireless transceiver / receiver unit is configured to send messages to a network, such as a serving network, where the messages indicate one or more channel status information (CSI) measurements supported by the WTRU, receive multiple reference signals (RS), where each of the multiple RS is associated with multiple configured resource sets, determine the respective sensing performance value for each of the configured resource sets associated with the multiple RS based on the mutual information (MI) associated with the multiple RS, determine the respective set of precoding matrix indicators (PMI) for each of the configured resource sets based on the respective sensing performance value for each of the configured resource sets, and send a sensing report showing the respective set of PMI and the respective sensing performance value for each of the configured resource sets.

Description

[Background technology]

[0001] Typically, sensing involves a beam scanning procedure by a transmitter entity, generating a sweep beam to cover a target area in the environment (e.g., sequentially, the receiver captures their reflections). In bistatic and multistatic sensing, a measuring entity (e.g., a wireless transceiver / receiver unit; WTRU) must detect one or more signal copies reflected by the environment from one or more sensing beams and perform measurements (e.g., delay, power, angle of arrival; AoA) to identify the scatterers. In monostatic sensing, the receiving entity is located in the same location as the transmitter. It performs detection simultaneously with transmission (e.g., in full-duplex mode) or after transmission is complete (e.g., in half-duplex mode).

[0002] A bistatic or multistatic scenario may include one or more transmission reception points (TRPs) as transmitting entities for downlink sensing, and one or more WTRUs as receivers for performing sensing measurements and returning the measurement results to the network. A similar bistatic or multistatic scenario may include two or more WTRUs, two or more base stations (BS), and / or a transmitting WTRU and a receiving BS.

[0003] Cross-reference of related applications This application claims the benefit of U.S. Provisional Application No. 63 / 518,908, filed on 11 August 2023, the entirety of which is incorporated herein by reference. [Overview of the project]

[0004] A wireless transceiver / receiver unit (WTRU) may include a processor. The processor may be configured to send messages to a network, such as a serving network. These messages may represent one or more channel status information (CSI) measurements supported by the WTRU. The processor may be configured to receive multiple reference signals (RS), each of which is associated with a configured resource set. The processor may be configured to determine the sensing performance value for each configured resource set associated with the multiple RSs, based on mutual information (MI) associated with the multiple RSs. The sensing performance value may be, for example, a minimum mean square error (MMSE) or mean square error (MSE) value below a threshold. For example, the sensing performance value of a configured resource set represents the statistical error associated with the sensing metric being measured for that configured resource set. In some examples, MI may be a metric characterizing the amount of information carried by the channels associated with each of the configured resource sets.

[0005] The processor may be configured to determine each set of precoding matrix indicators (PMIs) for each configured resource set based on the respective sensing performance values ​​for each configured resource set. For example, the processor may be configured to determine the set of PMIs based on the sensing performance values ​​of configured resource sets within a predetermined range.

[0006] The processor may be configured to send a sensing report for each configured resource set, showing the respective PMI set and its sensing performance value. In some examples, the sensing report may be a sensing codebook index for each Channel State Information (CSI) RS Resource Indicator (CRI).

[0007] The processor may be configured to receive configuration information that includes the spatial characteristics of multiple RSs.

[0008] The PMI set may be determined, for example, based on sensing performance values ​​for each configured resource set, within a predetermined range.

[0009] The message may be an indication of a performance metric supported for bistatic or multistatic sensing, and / or a sensing codebook supported by the WTRU. The performance metrics supported for bistatic or multistatic sensing may be any combination of (i) least mean squares error (MMSE), (ii) signal-to-noise ratio (SNR), (iii) reference signal received power (RSRP), (iv) root-squared (RMS) error of the distance estimation, (v) RMS error of the angle of arrival (AoA) estimation, (vi) RMS error of the phase estimation, and / or (vii) RMS error of the velocity estimation.

[0010] A WTRU may be configured to perform one or more of the following steps: The method may include sending a message to a network, for example, a serving network. The message may represent one or more channel status information (CSI) measurements supported by the WTRU. The method may include receiving multiple reference signals (RS), each of which is associated with a configured resource set. The method may include determining a sensing performance value for each of the configured resource sets associated with the multiple RSs, based on mutual information (MI) associated with the multiple RSs. The sensing performance value may be, for example, a least mean squares error (MMSE) or mean squares error (MSE) value below a threshold. For example, the sensing performance value of a configured resource set represents the statistical error associated with the sensing metric being measured for the configured resource set. In some examples, MI may be a metric that characterizes the amount of information carried by the channels associated with each of the configured resource sets.

[0011] The method may include determining each set of precoding matrix indicators (PMIs) for each configured resource set based on the respective sensing performance values ​​for each configured resource set. For example, the method may include determining the set of PMIs based on the sensing performance values ​​of configured resource sets within a predetermined range.

[0012] The method may involve sending a sensing report for each configured resource set, showing the respective PMI set and its sensing performance value. In some examples, the sensing report may be a sensing codebook index per Channel Status Information (CSI) RS Resource Indicator (CRI).

[0013] The method may include receiving configuration information that includes the spatial characteristics of multiple RSs.

[0014] The PMI set may be determined, for example, based on sensing performance values ​​for each configured resource set within a predetermined range.

[0015] The message may be an indication of a performance metric supported for bistatic or multistatic sensing, and / or a sensing codebook supported by the WTRU. The performance metrics supported for bistatic or multistatic sensing may be any combination of (i) least mean squares error (MMSE), (ii) signal-to-noise ratio (SNR), (iii) reference signal received power (RSRP), (iv) root mean square (RMS) error of the distance estimation, (v) RMS error of the angle of arrival (AoA) estimation, (vi) RMS error of the phase estimation, and / or (vii) RMS error of the velocity estimation.

[0016] A more detailed understanding can be obtained from the following "Modes for Carrying Out the Invention," which are given as examples in conjunction with the drawings accompanying this specification. The figures in these drawings are illustrative, as are the "Modes for Carrying Out the Invention." Therefore, the figures and the "Modes for Carrying Out the Invention" should not be considered limiting, and other equally effective examples may be possible. Note that the same reference numeral ("ref.") in the figures indicates the same element. [Brief explanation of the drawing]

[0017] [Figure 1A] This is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used in the communication system shown in Figure 1A, according to an embodiment. [Figure 1C]It is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used in the communication system shown in FIG. 1A, according to an embodiment. [Figure 1D] It is a system diagram illustrating another example RAN and another example CN that may be used in the communication system shown in FIG. 1A, according to an embodiment. [Figure 2] It is a system diagram illustrating an example monostatic sensing scenario implemented by a transmission / reception point (TRP). [Figure 3] It is a system diagram illustrating an example bistatic sensing including a TRP and a plurality of WTRUs. [Figure 4] It is a system diagram illustrating an example multistatic sensing including a TRP and a plurality of WTRUs. [Figure 5] It is a system diagram showing an example of bistatic sensing including a sensing beam and a sensing direction, which includes a TRP and a WTRU. [Figure 6] It is a system diagram showing an example scenario of bistatic sensing including a TRP, a WTRU, and a plurality of scatterers. [Figure 7] It is a system diagram illustrating example sensing CSI acquisition and reporting by a WTRU assisted by RS for sensing CSI acquisition. [Figure 8] It is a flow diagram illustrating an example method for sensing CSI acquisition by a WTRU. [Figure 9] It is a system diagram of example bistatic sensing measurements performed by a WTRU assisted by sensing RS over one or more active transmission configuration indicator (TCI) states for sensing. [Figure 10] It is a flowchart diagram illustrating an example bistatic / multistatic sensing and reporting method by a WTRU. DETAILED DESCRIPTION OF EMBODIMENTS

[0018] The following detailed description provides several specific details to ensure a full understanding of the embodiments and / or examples disclosed herein. However, it should be understood that such embodiments and examples may be practiced without some or all of the specific details shown herein. In other examples, well-known methods, procedures, components, and circuits are not described in detail so as not to obscure the following description. Furthermore, embodiments and examples not specifically described herein may be practiced in place of, or in combination with, the embodiments and other examples described, disclosed, or otherwise explicitly, implicitly, and / or essentially provided herein (collectively, the “Provided”). Various embodiments of apparatus, systems, devices, etc., and / or any of their components, performing operations, processes, algorithms, functions, etc., and / or any part thereof, are described and / or claimed herein, but it should be understood that any embodiment described and / or claimed herein assumes that any apparatus, system, device, etc., and / or any of their components are configured to perform any operation, process, algorithm, function, etc., and / or any part thereof.

[0019] The methods, apparatus, and systems provided herein are suitable for communications, including both wired and wireless networks. Outlines of various types of wireless devices and infrastructure are provided with respect to Figures 1A to 1D, and various elements of a network may utilize, implement, arrange accordingly, and / or adapt and / or configure for the methods, apparatus, and systems provided herein.

[0020] Figure 1A shows an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messages, and broadcasts to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 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), quadrature FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail intrinsic word DFT spread OFDM (ZT UW DTS-s OFDM), intrinsic word OFDM (UW-OFDM), resource block filtering OFDM, filter bank multicarrier (FBMC), and similar.

[0021] As shown in Figure 1A, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it should be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRUs 102a, 102b, 102c, and 102d, all sometimes referred to as “stations” and / or “STAs,” may be configured to transmit and / or receive wireless signals and may include user equipment (UEs), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots or / or other wireless devices operating in industrial and / or automated processing chain situations), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, and similar. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs. Furthermore, the descriptions provided herein with reference to the UE may also apply to the WTRU (and vice versa). For example, a WTRU may be configured to perform any of the processes or procedures described herein as being performed by the UE (and vice versa).

[0022] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be a base transceiver station (BTS), Node-B, eNodeB, home node B, home eNodeB, gNB, NR NodeB, site controller, access point (AP), wireless router, and similar. Although base stations 114a and 114b are depicted as single elements, it should be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0023] Base station 114a may be part of 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), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be called cells (not shown). These frequencies may be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectra. A cell may provide coverage for a wireless service to a particular geographic area, which may be relatively fixed or change over time. This cell may further be divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver per sector of the cell. In embodiments, the base station 114a may employ multiple-input multiple-output (MIMO) technology, and multiple transceivers may be available in each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0024] Base stations 114a and 114b may communicate with one or more WTRUs 102a, 102b, 102c, and 102d via 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).

[0025] More specifically, as described above, the communication system 100 may be a multiplex access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 / 113 may implement radio technology such as Universal Mobile Communications System (UMTS) Terrestrial Radio Access (UTRA), which may establish air interfaces 115 / 116 / 117 using broadband 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).

[0026] In the embodiment, the base station 114a and WTRUs 102a, 102b, 102c may implement a radio technology such as Advanced UMTS Terrestrial Radio Access (E-UTRA), which can establish an air interface 116 using Long-Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0027] In the embodiment, the base station 114a and WTRUs 102a, 102b, 102c may implement radio technology such as NR radio access, which can establish an air interface 116 using New Radio (NR).

[0028] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. 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 and from multiple types of base stations (e.g., eNB and gNB).

[0029] In other embodiments, base stations 114a and WTRUs 102a, 102b, 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate for GSM Evolution (EDGE), GSM EDGE (GERAN), and similar.

[0030] The base station 114b in Figure 1A may be, for example, a wireless router, home node B, home enode B, or access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as offices, homes, vehicles, campuses, industrial facilities, aerial walkways (e.g., for use by drones), roads, and the like. In one embodiment, the base station 114b and WTRUs 102c, 102d may implement radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In some embodiments, the base station 114b and WTRUs 102c, 102d may implement radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. As shown in Figure 1A, base station 114b may have a direct connection to the internet 110. Therefore, base station 114b may not be required to access the internet 110 via CN 106 / 115.

[0031] RAN 104 / 113 may communicate with 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 WTRUs 102a, 102b, 102c, and 102d. The data may have varying quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobile requirements, and so on. CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, internet connectivity, video distribution, and / or implement high-level security features such as user authentication. Although not shown in Figure 1A, it should be understood that RAN 104 / 113 and / or CN 106 / 115 may communicate directly or indirectly with other RANs employing the same or different RATs as RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113, which may be utilizing NR radio technology, CN 106 / 115 may also be communicating with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0032] CN 106 / 115 can also function as a gateway for WTRU 102a, 102b, 102c, and 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing legacy telephone services (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmit Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) of the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, but these CNs may employ the same RAT as RAN 104 / 113 or a different RAT.

[0033] Some or all of the WTRUs 102a, 102b, 102c, and 102d of the communication system 100 may include multimode functionality (for example, WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a which may employ cellular-based radio technology and with base station 114b which may employ IEEE 802 radio technology.

[0034] Figure 1B is a system diagram showing an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 may particularly 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 supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripherals 138. It should be understood that the WTRU 102 may include any subcombination of the aforementioned elements while maintaining consistency with the embodiment.

[0035] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors coupled with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, 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 functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120 which may be coupled to a transmit / receive element 122. Although Figure 1B depicts the processor 118 and transceiver 120 as separate components, it should be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0036] The transmit / receive element 122 may be configured to transmit signals to or from a base station (e.g., base station 114a) via 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 another embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It should be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0037] Although the transmit / receive element 122 is depicted as a single element in Figure 1B, 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 via the air interface 116.

[0038] The transceiver 120 may be configured to modulate the signal to be transmitted by the transmit / receive element 122 and to demodulate the signal received by the transmit / receive element 122. As described above, the WTRU 102 may have multimode capabilities. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate by multiple RATs, such as NR and IEEE 802.11.

[0039] The processor 118 of WTRU 102 is coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and can receive user input data from them. The processor 118 can also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 can access information from and store data in any suitable memory of any type, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a subscriber identification module (SIM) card, a memory stick, a secure digital (SD) memory card, and similar. In other embodiments, the processor 118 may access information from memory not physically located in the WTRU 102, such as a server or home computer (not shown), and may store data in that memory.

[0040] The processor 118 may receive power from the power supply 134 and may be configured to distribute and / or control power to other components of the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 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.

[0041] The processor 118 may also be coupled to a GPS chipset 136 which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be understood that the WTRU 102 may acquire location information by any suitable location determination method while maintaining consistency with the embodiment.

[0042] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photography and / or video), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulation (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 similar. Peripheral 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, compass sensor, proximity sensor, temperature sensor, time sensor; geolocation sensor; altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biosensor, and / or humidity sensor.

[0043] WTRU 102 may include a full-duplex radio, for which the transmission and reception of some or all of the signals (e.g., associated with specific subframes of both UL (e.g., for transmission) and downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference by hardware (e.g., chokes) or by signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In embodiments, WRTU 102 may include a half-duplex radio, for which the transmission and reception of some or all of the signals (e.g., associated with specific subframes of either UL (e.g., for transmission) or downlink (e.g., for reception)) may be parallel and / or simultaneous.

[0044] Figure 1C is a system diagram showing RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 may employ E-UTRA radio technology to communicate with WTRU 102a, 102b, and 102c via the air interface 116. RAN 104 may also communicate with CN 106.

[0045] RAN 104 may include eNode-B 160a, 160b, and 160c, but it should be understood that RAN 104 may include any number of eNode-B while maintaining consistency with the embodiment. Each of the eNode-B 160a, 160b, and 160c may include one or more transceivers for communicating with WTRU 102a, 102b, and 102c via the air interface 116. In one embodiment, eNode-B 160a, 160b, and 160c may implement MIMO technology. Thus, eNode-B 160a may use multiple antennas, for example, to transmit and / or receive wireless signals to and from WTRU 102a.

[0046] Each of the eNode-B 160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, and similar matters. As shown in Figure 1C, the eNode-B 160a, 160b, and 160c may communicate with each other via the X2 interface.

[0047] The CN 106 shown in Figure 1C 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 aforementioned elements is depicted as part of CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0048] MME 162 may be connected via the S1 interface to each of the eNode-B 162a, 162b, and 162c within RAN 104 and can function as a control node. For example, MME 162 may be responsible for user authentication of WTRU 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial connection of WTRU 102a, 102b, and 102c, and similar tasks. MME 162 may provide control plane functionality for switching between RAN 104 and other RANs (not shown) employing GSM and / or other radio technologies such as WCDMA.

[0049] SGW 164 can be connected to eNode B 160a, 160b, and 160c in RAN 104 via the S1 interface. SGW 164 can generally route and forward user data packets to and from WTRU 102a, 102b, and 102c. SGW164 can perform other functions, such as anchoring the user plane during inter-eNode B handovers, triggering paging when DL data is available to WTRU 102a, 102b, and 102c, managing and remembering the context of WTRU 102a, 102b, and 102c, and similar functions.

[0050] SGW 164 may be connected to PGW 166, which provides WTRU 102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU 102a, 102b, and 102c and IP-enabled devices.

[0051] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRU 102a, 102b, and 102c with access to a circuit-switched network such as PSTN 108 to facilitate communication between WTRU 102a, 102b, and 102c and conventional fixed telephone line communication devices. For example, CN 106 may include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and PSTN 108. In addition, CN 106 can also provide WTRU 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0052] While the WTRU is depicted as a wireless terminal in Figures 1A to 1D, in some representative embodiments, it is intended that such a terminal may be able to use a wired communication interface with a communication network (e.g., temporarily or permanently).

[0053] In a typical embodiment, the other network 112 may be a WLAN.

[0054] A WLAN in Infrastructure Basic Service Set (BSS) mode may have access points (APs) for the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with a distribution system (DS) or another type of wired / wireless network that brings traffic into and / or out of the BSS. Traffic originating outside the BSS to an STA may arrive via an AP and be delivered to the STA. Traffic originating from an STA to a destination outside the BSS may be sent to an AP to be delivered to its respective destination. Traffic between STAs within the BSS may be sent via an AP; for example, a source STA may send traffic to an AP, which may then deliver that traffic to a destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between a source STA and a destination STA (e.g., directly between them) using a Direct Link Setup (DLS). In some typical embodiments, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs (e.g., all STAs) within or using IBSS may communicate directly with each other. The IBSS mode of communication may, in this specification, be referred to as the “ad-hoc” mode of communication.

[0055] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may be of a fixed width (e.g., 20 MHz wideband) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STA to establish a connection with the AP. In some typical embodiments, carrier-sense multiple access with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. In CSMA / CA, the STA, including the AP (e.g., all STAs), may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that particular STA will backoff. One STA (e.g., only one station) may transmit at any given time on a given BSS.

[0056] High-throughput (HT) STAs can use a 40MHz wide channel for communication by, for example, a combination of a primary 20MHz channel and adjacent or non-adjacent 20MHz channels to form a 40MHz wide channel.

[0057] Ultra-high throughput (VHT) STAs can support 20MHz, 40MHz, 80MHz, and / or 160MHz wide channels. 40MHz and / or 80MHz channels can be formed by combining consecutive 20MHz channels. 160MHz channels can be formed by combining eight consecutive 20MHz channels or two discontinuous 80MHz channels, sometimes referred to as an 80+80 configuration. In an 80+80 configuration, data can be passed through a segment parser that, after channel encoding, can split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time-domain processing are performed separately for each stream. The streams can be mapped to two 80MHz channels, and the data can be transmitted by a transmitting STA. At the receiver of a receiving STA, the above operation of the 80+80 configuration may be reversed, and the combined data may be sent to a medium access control (MAC) layer.

[0058] Sub-1GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV white space (TVWS) spectrum, while 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using the non-TVWS spectrum. According to a typical embodiment, 802.11ah may support meter-type control / machine-type communications (MTC), such as MTC devices in the macro-coverage region. MTC devices may have limited capabilities, e.g., limited capabilities including support for specific and / or limited bandwidths (e.g., only support). MTC devices may include batteries with battery life exceeding a threshold (e.g., to maintain very long battery life).

[0059] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as the primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA that supports the minimum bandwidth operating mode among all STAs operating in the BSS. In the 802.11ah example, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only supports) 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 state of the primary channel. If the primary channel is busy, for example, because of an STA (which only supports 1MHz operating mode) transmitting to the AP, the entire available frequency band may be considered busy, even though a large portion of the frequency band could remain idle and be available.

[0060] In the United States, the available frequency band for 802.11ah is from 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz, and in Japan, it is from 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is from 6 MHz to 26 MHz, depending on the country code.

[0061] Figure 1D is a system diagram showing RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 may employ NR radio technology to communicate with WTRU 102a, 102b, and 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0062] RAN 113 may include gNBs 180a, 180b, and 180c, but it should be understood that RAN 113 may include any number of gNBs while maintaining consistency with the embodiment. Each of the gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via the air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and from gNBs 180a, 180b, and 180c. Thus, gNB 180a may use multiple antennas to transmit and / or receive wireless signals to and from WTRU 102a, for example. In embodiments, gNBs 180a, 180b, and 180c may implement carrier aggregation techniques. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be in the unlicensed spectrum, and the remaining component carriers may be in the licensed spectrum. In embodiments, gNBs 180a, 180b, and 180c may implement coordinated multipoint (CoMP) techniques. For example, WTRU 102a may receive coordinated transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0063] WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable numerical values. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, different cells, and / or different parts of the wireless transmission spectrum. WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or lasting for a varying absolute time length).

[0064] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-B 160a, 160b, and 160c). In a standalone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using unlicensed band signals. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c while also communicating with other RANs such as eNode-B 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more eNode-B 160a, 160b, and 160c. In a non-standalone configuration, eNode-B 160a, 160b, and 160c can function as mobility anchors for WTRU 102a, 102b, and 102c, while gNB 180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU 102a, 102b, and 102c.

[0065] Each of the gNBs 180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling during UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data for user plane functions (UPF) 184a and 184b, routing of control plane information for access and mobility management functions (AMF) 182a and 182b, and similar functions. As shown in Figure 1D, the gNBs 180a, 180b, and 180c may communicate with each other via the Xn interface.

[0066] The CN 115 shown in Figure 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the aforementioned elements is depicted as part of CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0067] AMF 182a and 182b may be connected to one or more of gNB 180a, 180b, and 180c in RAN 113 via the N2 interface and may function as control nodes. For example, AMF 182a and 182b may be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF 183a and 183b, managing registration areas, terminating NAS signaling, mobility management, and similar tasks. Network slicing may be used by AMF 182a and 182b to customize CN support for WTRU 102a, 102b, and 102c based on the type of services utilized by WTRU 102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-high reliability low latency (URLLC) access, services relying on enhanced large-scale mobile broadband (eMBB) access, services for machine-type communications (MTC) access, and / or similar. AMF 162 may provide control plane functionality for switching between RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0068] SMF 183a and 183b may be connected to AMF 182a and 182b in CN 115 via the N11 interface. SMF 183a and 183b may also be connected to UPF 184a and 184b in CN 115 via the N4 interface. SMF 183a and 183b may select and control UPF 184a and 184b and configure the routing of traffic through UPF 184a and 184b. SMF 183a and 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and similar. PDU session types may be IP-based, non-IP-based, Ethernet-based, etc.

[0069] UPF 184a and 184b may be connected via the N3 interface to one or more of the gNBs 180a, 180b, and 180c in RAN 113, which may provide WTRU 102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU 102a, 102b, and 102c and IP-enabled devices. UPF 184 and 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, and providing mobility anchors.

[0070] CN 115 may facilitate communication with other networks. For example, CN 115 may include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. In addition, CN 115 may provide WTRU 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via UPFs 184a, 184b through an N3 interface with UPFs 184a, 184b and an N6 interface between UPFs 184a, 184b and DNs 185a, 185b.

[0071] Considering Figures 1A to 1D and their corresponding descriptions, one or more, or all, of the functions described herein with respect to one or more of the WTRU 102a to d, Base Station 114a to b, eNode-B 160a to c, MME 162, SGW 164, PGW 166, gNB 180a to c, AMF 182a to ab, UPF 184a to b, SMF 183a to b, DN 185a to b, and / or any other devices described herein may be implemented by one or more emulation devices (not shown). These emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0072] Emulation devices may be designed to perform tests on one or more other devices in a laboratory and / or operator network environment. For example, one or more emulation devices may perform one or more or all of the functions of other devices in a communications network, while being fully or partially implemented and / or deployed as part of a wired and / or wireless communications network. One or more emulation devices may perform one or more or all of the functions of other devices, while being temporarily implemented / deployed as part of a wired and / or wireless communications network. Emulation devices may be directly coupled to another device for testing and / or may perform testing using wireless communications.

[0073] One or more emulation devices may perform one or more functions, including all of them, even though they are not implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test scenario in a test laboratory, and / or in a wired and / or wireless communication network that is not deployed (e.g., to be tested), to perform testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling, and / or wireless communication via RF circuitry (e.g., which may include one or more antennas), may be used by the emulation device to transmit and / or receive data.

[0074] Methods and procedures for bistatic sensing and multistatic sensing using wireless signals in a cellular environment may be provided.

[0075] Sensing can refer to estimating one or more spatial properties (e.g., absolute or relative position, 3D orientation, velocity, etc.) of one or more objects that are not wirelessly connected to the system under consideration. In some wireless systems, sensing may be considered part of the communication framework, for example, when considering integrated sensing and communication.

[0076] At least three sensing modes are typically established with respect to the object to be sensed, depending on the relative positions of the transmitter and receiver, or multiple receivers.

[0077] Figure 2 is a system diagram 200 illustrating an example of monostatic sensing performed by a Transmit / Receiver Point (TRP). Monostatic sensing refers to a scenario in which a transmitter entity and a receiver entity are located in the same place to estimate one or more of the position, velocity, and / or orientation of an object (e.g., an object). Monostatic sensing can be performed by a base station (BS) (e.g., a Transmit / Receiver Point (TRP)) or a WTRU. Sensing can be applied to detect one or more objects.

[0078] Figure 3 is a system diagram 300 showing an example of bistatic sensing including a TRP and a WTRU. Bistatic sensing refers to a scenario in which the transmitter and receiver entities are not located in the same place for sensing, for example, with the TRP acting as the transmitter and the WTRU as the receiver (as shown in the figure), or vice versa.

[0079] Figure 4 is a system diagram 400 illustrating an example of multistatic sensing including a TRP and multiple WTRUs. Multistatic sensing refers to a scenario in which multiple receiving entities (e.g., multiple WTRUs) sense one or more objects with the assistance of transmitting entities that are not located in the same place.

[0080] Monostatic sensing may require full-duplex capability (e.g., the ability to simultaneously transmit a sensing signal and detect reflections from the environment) in the sensing entity (e.g., a WTRU or TRP). Alternatively, monostatic sensing may be implemented in half-duplex mode by performing detection over a receive window that begins when transmission is complete, using, for example, a detection technique that is not based on the Discrete Fourier Transform (DFT) and utilizes only a portion of the reflected signal. Bistatic and multistatic sensing can be implemented without using full-duplex mode because the transmitting and receiving entities are different.

[0081] Sensing methods can also be distinguished as active sensing or passive sensing depending on whether the sensing involves transmitting a presumably known signal and subsequently detecting the reflected signal (e.g., in an active case), or whether it involves only detecting the reflected signal (e.g., in a passive case). The methods and procedures described later generally refer to the case of active sensing, but can also be applied to passive sensing.

[0082] Channel status information (CSI) refers to a set of quantities that a communication entity (e.g., a TRP or WTRU) can acquire to describe the channel status, frequency, and / or spatial domain characteristics at any given time. CSI can be measured by the network and / or WTRU to acquire UL channel status and DL channel status, respectively, and further to optimize communication performance. CSI can be equal in UL and DL when channel mutual conditions persist, for example with respect to a TDD system using a mutual transceiver architecture.

[0083] In some existing solutions, DL CSI may be measured by WTRU with the assistance of, for example, a set of CSI-RS signals or an SS / PBCH block. For example, an SS / PBCH block (SSB) may carry a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), and / or a PBCH demodulated reference signal (DMRS), all of which can assist in determining DL CSI. DL CSI information may include various measurements configured by the network in broadband or subband modes, such as RSRP, CQI, PMI, RI, etc.

[0084] UL CSI can be measured by a network, for example, with the assistance of a sounding reference signal (SRS), and / or US CSI can be acquired by WTRU at DL and reported back to the base station if channel reciprocity conditions persist. UL CSI may include quantities similar to DL CSI. For example, UL CSI may include RSRP, CQI, PMI, RI, and / or similar.

[0085] Figure 5 is a system diagram illustrating an exemplary sensing scenario showing the sensing beam and sensing direction for bistatic sensing. When scanning a medium for bistatic or multistatic sensing, some sensing beams may fail to reach their intended target (e.g., an object). For example, some sensing beams may fail to reach their intended target when the beam is pointed in a direction that presents no meaningful objects or is too far away to be detected. Without hints about the optimal beam configuration and / or the direction in which to sense the medium, resources and / or energy spent on sensing transmissions may be wasted on unproductive sensing attempts.

[0086] WTRUs can assist the network in configuring and / or refining beams in the optimal direction for bistatic and multistatic sensing. WTRUs can report relevant data, for example, to help optimize sensing procedures. One or more methods and procedures for bistatic and multistatic sensing using wireless signals in a cellular environment may be provided.

[0087] In this specification, "TRP" may be used interchangeably with "gNB".

[0088] In this specification, “target,” “scatterer,” and “object” may be used interchangeably to refer to any obstacle to be sensed that is not wirelessly connected to the system under consideration.

[0089] In this specification, the term "sensing beam" may be used to refer to a spatial domain filter used to transmit or receive a sensing reference signal.

[0090] In this specification, "sensing RS" may be used to refer to any reference signal for bistatic or multistatic sensing.

[0091] In this specification, “sensing CSI” may be used to refer to any channel measurement result obtained by a receiving entity from a composite channel comprising a transmitter, an object, and a receiver that can be utilized for sensing.

[0092] In this specification, “Sensing PMI” may refer to a representation of the sensing precoding matrix (e.g., an index in a codebook of a predefined precoding matrix representing the discretization direction of the sensing). Sensing PMI can be, for example, part of the sensing CSI acquisition process performed by the UE.

[0093] In this specification, the terms “sensing precoding matrix codebook” or “sensing codebook” may be used to refer to any set of precoding matrices for transmitting sensing RS along a predefined set of directions.

[0094] In this specification, the term "RS for sensing CSI acquisition" may be used to refer to any RS used to acquire sensing CSI information. Without loss of generality, it is assumed that it is an N-port signal, i.e., it enables sensing CSI acquisition for up to N antenna ports.

[0095] In this specification, "sensing TCI state" and "sensing TCI state" may be used interchangeably to refer to a set of quasi-collocation (QCL) relationships between the sensing RS and the sensing CSI acquisition RS corresponding to the sensing beam.

[0096] In this specification, "MPC" may be used to refer to any of the multipath components received by the UE when detecting scattered and reflected signals from the environment.

[0097] In this specification, “port” and “antenna port” may be used to refer to any signal whose channel characteristics can be clearly determined by any suitable RS-assisted receiver. A signal mapped to an antenna port may be transmitted by one or more physical antennas.

[0098] Figure 6 is a system diagram 600 illustrating an exemplary scenario of bistatic sensing using TRPs, WTRUs, and multiple scatterers. A cellular scenario may involve one or more TRPs whose purpose is to sense the environment with the help of one or more WTRUs, which perform sensing measurements to derive spatial information about surrounding objects, such as their position, velocity, and orientation, as determined by the system or application.

[0099] The TRP may have any number of transmit and receive antennas, such as in a large-scale multiple-input multiple-output (M-MIMO) configuration. The number of antenna ports N may be signaled to the WTRU as part of a sensing configuration corresponding to the maximum number of antenna ports available for transmitting sensing RS signals, sensing RS for CSI acquired signals, or both. The WTRU may be equipped with one or more receive antennas.

[0100] A suitable RS for sensing measurements may already exist in the form of either an existing signal reused for another sensing purpose, such as a DL positioning reference signal (PRS) or positioning UL sounding reference signal (SRSp) in 5G NR, or a dedicated sensing signal. A suitable RS for sensing CSI acquisition may already exist, such as a CSI-RS, SSB, or any other signal.

[0101] Signal waveforms capable of frequency domain analysis may be applicable. For example, OFDM-like waveforms, such as CP-OFDM or DFT-s-OFDM, with discrete samples in the time domain or frequency domain, may be applicable. Other waveforms may be similarly applicable.

[0102] Bistatic and multistatic sensing can be optimized by dynamically selecting one or more directions that yield the best possible sensing performance (e.g., sensing accuracy as expressed by its MMSE), and / or discarding one or more directions that are not optimal for sensing.

[0103] Measurement of sensing CSI information can be implemented.

[0104] Sensing channel metrics that can help determine the spatial direction in which sensing accuracy is best possible within the bistatic or multistatic scenario. These channel metrics may be expressed as sensing CSI or sensing CSI information.

[0105] Measurement of sensing CSI and selection of spatial orientation are performed using a WTRU to obtain the minimum size of MMSE that can be perceived (e.g., delay, AoA, etc.). Other criteria may also be equally valid for measuring and reporting the amount of sensing CSI information using a WTRU.

[0106] The spatial direction of sensing can be discretized and signaled as an index within the sensing codebook (e.g., by sensing PMI). In this specification, the term “sensing PMI” is used, but any other naming convention may be applied.

[0107] The relationship link between the mutual information (MI) available on a given channel and the estimated MMSE of the parameters can be expressed by the following equation (1).

[0108]

number

[0109] However, the equation on the left represents the derivative with respect to SNR, MMSE is the smallest perceived magnitude of MSE, and MI is the mutual information between the input and output of a channel in the presence of additive white Gaussian noise (AWGN). Equation (1) applies regardless of the statistical data of the input signal supplied to the channel. MI can also be a metric that characterizes the amount of information carried by the channel associated with each of the configured resource sets.

[0110] In some solutions, equation (1) is the threshold ε max It is used as a base to identify the beam and spatial direction that presents the MMSE for sensing less than (for example, sometimes called the sensing MMSE), and thus the optimal sensing direction can be expressed as shown in equation (2) below.

[0111] MMSE<ε max (2) Another criterion besides the sensing MMSE may be used to select the optimal sensing direction.

[0112] A predefined set of sensing beams may be assumed. These sensing beams may be identified by an appropriate index containing an identifier for the resource set in 5G NR, such as a CSI-RS resource indicator (CRI) or any other direct or indirect means. Furthermore, the codebook of the sensing precoding matrix may be speculative, and its entries are identified by a codebook index represented by the sensing PMI. The codebook may represent a set of precoding matrices for transmitting sensing signals along any of the predefined sets of sensing directions.

[0113] Figure 7 is a system diagram 700 showing an example of sensing CSI acquisition and reporting by a WTRU assisted by a sensing CSI acquisition RS. In Figure 7, several sensing beams, including appropriate sensing CSI acquisition RSs, are used by the WTRU to derive the sensing MMSE with the help of equation (1). The receiver (e.g., WTRU) may select an appropriate set of sensing beams and codebook indices for sensing that satisfies equation (2). Beams may be identified by their CRI, as in 5G NR, but other arbitrary identifiers are equally valid.

[0114] Sensing precoding matrix indicator (PMI) values ​​may be measured from one or more sensing beams transmitted by a TRP or other device. One or more sensing PMI values ​​may be obtained for each sensing beam. For example, the association between sensing beams and sensing PMI values ​​may be reported as a set of sensing PMI values ​​in a given CRI that present an MMSE below a threshold. For example, sensing PMI values ​​may not be associated with a given CRI if their MMSEs exceed a threshold, or if it is impossible to obtain an MMSE due to a low SNR or insufficient SNR variation necessary to reliably calculate the derivative of the MI.

[0115] Acquired sensing PMI values ​​corresponding to one or more sensing beams may be reported by the WTRU as part of a sensing report that includes channel measurement results for sensing.

[0116] The sensing MMSE value can be calculated from the derivative of the mutual information with respect to the SNR according to equation (1), regardless of whether the channel is of AWGN type or Rayleigh type.

[0117] M-QAM modulation set M constellation symbol x i For a distance d in the complex plane, i The dispersion amount ρ is located at this point. 2 Assuming a receiving constellation symbol y affected by an AWGN having , the MI can be obtained using the following equation (3):

[0118]

number

[0119] however,

[0120]

number

[0121] represents a known x i expectation operator for a symbol y conditioned on the coordinates of,

[0122] [Math.]

[0123] represents the log-likelihood ratio for the transmission of x i and the transmission of any other symbol, and may be given by the following equation (4).

[0124] [Math.]

[0125] The LLR value may be calculated by the WTRU based on the parameter d i / σ 2 by applying equation (4), or by means of a lookup table that approximates equation (4) for each modulation order M.

[0126] A symbol may experience a frequency-flat channel response, so equations (3) and (4) may be applied directly. Alternatively or additionally, a symbol may be affected by a Rayleigh fading channel, whereby the frequency characteristic of the transmitted signal is not sustained and the received signal may exhibit a frequency-selective response. LLR calculation may be performed after channel equalization to restore the frequency characteristic of the signal. The detected signal after equalization may be considered to be affected by AWGN, and the noise power thereof may be given by the sum of thermal noise and impairments resulting from the equalization process including transceiver imperfections such as phase noise that increases to composite noise power, non-linearity, I / Q imbalance, and / or others. In such cases, the post-equalization SNR and the value of σ 2 (e.g., which may be referred to as post-detection values) may be considered for equation (4).

[0127] LLR calculations are reciprocal between UL and DL in time-division duplex (TDD) systems where the same frequency is used for UL and DL. It is assumed that the system transceivers are designed to respond reciprocally (for example, their behavior can be considered identical for UL and DL). In this case, the channel states will be identical for UL and DL, and the LLR values ​​may also be identical. In other cases, such as frequency-division duplex (FDD) systems, the frequencies and channel states differ for UL and DL, and therefore their LLR calculations may be non-reciprocal.

[0128] MI is the equalized received signal vector.

[0129]

number

[0130] (N is the number of antenna ports for transmitting RS for sensing CSI acquisition), sensing

[0131]

number

[0132] It is obtained after multiplying by one of the precoding matrices for 0≦i≦N-1, thereby the received signal

[0133]

number

[0134] This can be obtained. The received signal and the ideally transmitted M constellation symbols {d k The distance between {1 ≤ k ≤ M, k ≠ i} is further calculated, substituted into equation (4), and input into equation (3).

[0135]

number

[0136] The value can be retrieved.

[0137] The equalized SNR cannot be considered constant across frequencies, for example, when the channel frequency response is not constant across RS resources used for sensing CSI acquisition. The derivative of MI with respect to SNR is of the form {snr + (Δsnr) j It can be approximated by a set of P distinct SNR values ​​{j=1,...,P}, where (Δsnr) j The small deviation around a given SNR is expressed using the following equation (5):

[0138]

number

[0139] However, (ΔMI) j This is the given SNR variation (Δsnr) j This represents the variation in the j-th MI that occurs after the previous one.

[0140] The derivative of MI with respect to SNR can be obtained from the following equation (6).

[0141]

number

[0142] However, snr eff This represents the SNR of the equivalent Gaussian channel, which yields the same MI as the actual instantaneous channel. eff The value of can be obtained by link-to-system methods such as Mutual Information Effective SINR Mapping (MIESM) and other methods. MIESM can provide the same MI as the actual instantaneous channel for the SNR of an ideal Gaussian channel. eff If can be obtained as a function of snr, then its derivative can also be obtained as a function of snr from equation (6).

[0143] In the link-to-system method, SNR effThe formula can be derived based on the following equation (7).

[0144]

number

[0145] However, I(x) is a function used to predict the BLER (e.g., MI or another), and α1 and α2 are embodiment-specific model parameters that are tuned to minimize the error between the BLER predicted by the model and the actual BLER at the modulation order and coding rate of the system's fit.

[0146] The derivative of MI with respect to the SNR of a channel whose response varies across frequencies can be obtained by calculating MI over a vector Gaussian channel. In this case, obtaining the mutual information may be more complex than equation (3).

[0147] A receiver (e.g., WTRU) may be configured to measure subband sensing PMI values ​​based on the MMSE criterion of Equation (2) for sets of subbands, each having a subset of the user-allocated bandwidth or a subset of the system bandwidth, respectively. The receiver may also be configured to measure broadband sensing PMI values ​​based on a broadband MMSE for a predefined frequency domain including the user-allocated bandwidth and / or the system bandwidth.

[0148] A subband sensing MMSE value can be derived from equation (1) for a given subband size, including a frequency domain that spans a subset of the frequency resources allocated for sensing CSI acquisition. For example, the frequency resources of the RS for sensing CSI acquisition can be subdivided into J non-overlapping subbands (J≧2) such that the channel frequency response can be considered constant in each subband, and that appropriate sensing MMSE values ​​can be obtained for each subband according to equation (1). The finer granularity of the subband sensing MMSE value is given by ε, where ε is the maximum MMSE. maxThis can be used to better allocate sensing RS resources to satisfy the requirements.

[0149] In contrast, the broadband sensing MMSE value can be derived for a wider range of frequencies allocated to the RS for sensing CSI acquisition, including user-allocated bandwidth and / or system bandwidth. The receiver (e.g., WTRU) may be configured to report the broadband sensing MMSE. In some solutions, the broadband sensing MMSE value can be obtained based on the effective SNR that yields the same MI as the actual channel of the current device, for example, as in equation (6). In some examples, the broadband sensing MMSE value can be obtained by the derivative of the cross-information of a vector channel obtained by considering the channel in J subbands.

[0150] The receiver may be configured to report a single broadband sensing MMSE, which is calculated as the maximum of J individual subband sensing MMSE values, as shown in equation (8) below.

[0151] MMSE wb =max{MMSE n ,1≦n≦J} (8) The receiver may be configured to report a single broadband sensing MMSE value equal to the average of the subband sensing MMSE values, including the arithmetic mean shown in equation (9).

[0152]

number

[0153] This method can be generalized to equation (7), obtained by replacing I(x) with the MMSE, by taking into account the geometric mean, harmonic mean, or other similar mean functions.

[0154] Other similar methods may also be conceivable, depending on the embodiment, to obtain broadband or subband PMI values ​​based on MMSE values ​​or any other suitable metric.

[0155] The subband or broadband precoding matrix of the sensing can be obtained for a number of predefined sensing directions to represent the appropriate spatial orientation of the sensing.

[0156] A codebook for the sensing precoding matrix, representing a set of spatial directions for sensing in one or more sensing beams, can be defined speculatively.

[0157] The codebook defines N precoding matrices (for example, type {

[0158]

number

[0159] The set may include {0 ≤ i ≤ N-1}. Each precoding matrix may include complex coefficients to be applied to the antenna ports to obtain N-port sensing transmit signals effectively directed in the desired spatial direction. Elements of the sensing codebook may be referred to as an index (e.g., sensing PMI), the selected value of which may be associated with one or more beams by an appropriate indicator (e.g., CRI value).

[0160] The codebook for sensing may be based on a codebook defined for communication purposes (e.g., a codebook containing precoding matrices for MIMO transmissions) or on a new codebook specifically for sensing.

[0161] A receiver (e.g., a WTRU) may receive one or more sensing beams. The equalized received signal vector for any of the received beams on the k-th subcarrier is {R k It is expressed as},

[0162]

number

[0163] The index k moves across a range of the set of subcarriers assigned to sensing. The equalized received signal vector at each of the received beams contains one or more (e.g., all) entries in the codebook (e.g.,

[0164]

number

[0165] The signal is multiplied by (0≦i≦N-1), and thereafter the received signal on the k-th subcarrier (for example,

[0166]

number

[0167] ) can be obtained. From these signals, the receiver may derive one or more precoding vectors for sensing for each sensing beam in broadband or subband format, based on the sensing MMSE reference or something else.

[0168] The actual precoding matrix used by the transmitter for sensing may or may not be based on sensing CSI feedback, and can simply be used by the transmitter as non-limiting feedback information. Furthermore, the precoding matrix used for transmission may be non-specific and transparent to the receiver, and may or may not be based on the reported PMI value.

[0169] Methods and procedures for acquiring and reporting sensing CSI information can be implemented, which may be used by the transmitter entity to optimize sensing performance in bistatic or multistatic scenarios.

[0170] A receiver (e.g., a WTRU) may send messages to the TRP, such as capability information messages, upon initial access to the system. These messages may include information about the WTRU's support for sensing and reporting CSI measurements. For example, a message might indicate one or more CSI measurements supported by the WTRU. This message may be sent during initial registration and can be transmitted via the uplink control channel or a shared channel.

[0171] The information contained in the capability message may include at least one of the following: (i) supported performance metrics for bistatic / multistatic sensing, (ii) a sensing codebook supported by the WTRU (e.g., indicated by an index in a predefined table), and / or (iii) reported sensing CSI measurements. The supported performance metrics for bistatic / multistatic sensing may include at least one of the following: (a) sensing MMSE, (b) SNR, (c) RSRP, (d) RMS error of the ranging (or delay) estimate, (e) RMS error of the AoA estimate, and / or (f) RMS error of the velocity estimate.

[0172] The reported sensing CSI measurement may include at least one of the following: (a) sensing codebook entries per resource set (e.g., in the form of sensing PMI values), (b) RSRP, post-detection SNR, or both values ​​for each sensing codebook entry, (c) sensing MMSE values ​​for each sensing codebook entry, (d) whether subband, broadband, or both reporting modes are supported for any of the above quantities, and / or (e) criteria for reporting broadband measurement results from acquired subband measurement results (e.g., if requested).

[0173] The criteria for reporting broadband measurement results from acquired subband measurement results may include at least one of the following: (A) the maximum, minimum, or average value (e.g., arithmetic mean, geometric mean, etc.) of the subband values; (B) broadband values ​​obtained from an equivalent AWGN channel that yields the same error performance as the actual channel (e.g., the same virtual BLER); and / or (C) broadband values ​​obtained for a vector Gaussian channel obtained by considering the actual channel response across J subbands.

[0174] The WTRU may be configured, indicated, or determined to measure and report the sensing CSI. For example, the WTRU may be configured with information about the spatial characteristics of the sensing beam (e.g., via RRC IE, DCI signaling, MAC CE, etc.). A first set of sensing RSs may be used to represent RSs intended to enable sensing CSI measurement by the WTRU, and a second set of sensing RSs may be used to represent RSs intended to enable bistatic or multistatic sensing measurement by the WTRU.

[0175] For example, a WTRU may acquire configuration information about a sensing beam through spatial relationships (e.g., as QCL characteristics) between a first set of RSs for sensing CSI acquisition and a second set of sensing RSs. These spatial characteristics may specify which channel quantities may be common to the sensing RSs and the RSs for sensing CSI acquisition (e.g., their delay spread, mean delay, Doppler spread, Doppler shift, received spatial filter, etc.). These can be explicitly defined, for example, or referred to as a set of predefined associations (e.g., in the form of sensing TCI states). Various subsets of TCI states may be defined to correspond to beams with different beamwidths, including some with wide beamwidths and others with narrow beamwidths. Narrow beams may be more suitable for bistatic and multistatic sensing due to their better angular resolution. In contrast, wide beams may be suitable for sensing CSI acquisition by a WTRU over a wider area where there are potentially multiple scatterers.

[0176] In some examples, the WTRU may acquire configuration information about the physical characteristics of the sensing beam, including angular directions such as azimuth and elevation angles, Euler rotation angles, and / or other arbitrary angular metrics called absolute or relative coordinate systems, and / or beam width (e.g., H-plane, V-plane, or bi-sided).

[0177] In some cases, the WTRU may be configured to measure and report sensing CSI information by RRC IE, DCI signaling, and / or MAC CE. Sensing CSI information may be reported in the form of broadband values ​​or as a collection of subband values. In the case of broadband, the network may constitute a criterion for obtaining broadband values ​​(e.g., based on maximum, minimum, and average values).

[0178] The sensing CSI configuration information may include at least one of the following: (i) a first set of sensing CSI acquisition RSs transmitted in a periodic, aperiodic, or semi-persistent manner; (ii) sensing performance metrics expressed as absolute or relative values, their tolerances for selecting the best precoding matrix index in the sensing codebook (e.g., sensing MMSE below a threshold), and indexes in a predefined table; and / or (iii) information about sensing CSI reporting.

[0179] The initial set of RSs for sensing CSI acquisition may be defined by (a) signal signals relating to sensing CSI measurement (e.g., SSB, CSI-RS, etc.), (b) the number of ports N per sensing beam, (c) a specified sensing resource set used for sensing CSI acquisition (e.g., as a list of resource set identifiers, an index in a table of resource set combinations, etc.), and / or (d) the starting RE, number of RBs, symbols and number of slots, a specified comb size and comb offset for each resource set, and / or, if no resource sets are defined globally, and in the case of periodic or semi-periodic RSs for sensing CSI acquisition, the periodicity of the RE with respect to the number of slots, frames, time duration, etc.

[0180] The signals used for sensing CSI measurements may be, for example, SSB signals used despite their limited spatial granularity and periodicity. In some cases, sparse signals of the signals used for CSI measurements may be adapted for sensing (e.g., CSI-RS). In some cases, a dedicated RS may be used for measurement.

[0181] The number of ports N per sensing beam may be equal to, for example, the number of entries in the sensing codebook.

[0182] Information about sensing CSI reporting may include at least one of the following: (A) an indication of whether sensing CSI reporting is aperiodic, periodic, or semi-permanent, and in the latter two cases, periodicity (e.g., with respect to the number of slots, time duration, etc.), and / or (B) an indication of whether broadband or subband reporting CSI is expected. The indication of whether broadband or subband reporting CSI is expected may include at least one of the following: (1) the number of subbands J as a value or index in a table of predefined values, (2) a specified subband size (e.g., as an index in a table of predefined subband sizes, etc.), and / or (3) a criterion for obtaining broadband performance metrics from a set of subband values.

[0183] Criteria for obtaining a broadband performance metric from a set of subband values ​​may include at least one of the following: (1) the maximum, minimum, or average value (e.g., arithmetic mean, geometric mean, harmonic mean, etc.) of the J subband values; (2) a broadband metric for an equivalent AWGN channel that yields the same error performance as the actual channel (e.g., virtual BLER); and / or (3) a broadband metric for a vector Gaussian channel obtained by considering the actual channel response across the J subbands.

[0184] Several broadband performance values ​​(e.g., sensing MMSE) can be associated with MI (e.g., by equation (1)). An equivalent AWGN channel may be defined such that the same virtual BLER (and therefore the same MI) as the actual channel is obtained in order to derive the broadband MMSE. The broadband value may be established as the (e.g., arithmetic mean, geometric mean, or harmonic mean) of the individual subband values. Other similar criteria may be followed to obtain broadband performance.

[0185] A WTRU may receive multiple RSs (for example, if each of the multiple RSs is associated with a configured resource set). For example, a WTRU may receive a first set of RSs for sensing CSI acquisition for each sensing configuration, such as SSB, CSI-RS, PRS, and dedicated sensing RS. Upon receiving the first set of RSs, the WTRU may perform at least one of several actions.

[0186] The WTRU can be obtained in one or more configured resource sets by, for example, removing known values ​​of RS complex symbols.

[0187] WTRU can remove the influence of channel response by, for example, applying an equalizer to reconstruct the frequency components of the signal, thereby obtaining equalized RS symbols and frequency-dependent post-detection SNR values ​​in one or more configured resource sets.

[0188] The WTRU can be obtained by multiplying the equalized RS symbol by each of the N precoding matrices in the sensing codebook, resulting in N frequency-dependent precoded signal vectors.

[0189] The WTRU may determine sensing performance values ​​for each configured resource set associated with multiple RSs, based on the mutual information (MI) associated with those RSs. For example, in the case of subband reporting by the WTRU, the WTRU may acquire configured sensing performance values, such as sensing MMSE, for each precoded signal vector in the configured subbands and resource sets. The sensing MMSE may be acquired, for example, as twice the derivative of the MI with respect to the post-detection SNR. The derivative of the MI may be approximated, for example, as the ratio of MI variation caused by the variation measured in the post-detection SNR. This approximation may be accurate, for example, when the SNR variation exceeds a pre-configured or fixed threshold, and when it does not exceed the threshold, the TRP is reported as not having acquired the sensing MMSE.

[0190] In the case of broadband reporting, the WTRU may obtain a single broadband sensing performance metric for the intended frequency allocation, per precoded signal vector and configured resource set. The performance set and configured resource set may be based on the average value (e.g., arithmetic mean, geometric mean, harmonic mean, etc.) of J subband performance values. The performance set and configured resource set may be based on the maximum or minimum value of J subband performance values. The performance set and configured resource set may be based on a performance metric of the effective AWGN channel that yields the same error performance (e.g., the same virtual BLER) as the actual channel. The performance set and configured resource set may be based on a performance metric of the vector Gaussian channel obtained by considering the actual channel response across J subbands.

[0191] The WTRU can compare the acquired performance values ​​to a configured range (e.g., one or more thresholds for comparing those values) for each configuration, and can determine a set of codebook entries (e.g., sensing PMIs) for each sensing resource set that satisfies the conditions. These conditions may include PMIs where the sensing performance value is within a specified range (e.g., sensing MMSE is below a threshold), and / or PMIs where the RSRP or post-detection SNR value exceeds a threshold. Thus, the WTRU can determine a set of PMIs for each configured resource set based on the sensing performance values ​​of the configured resource set.

[0192] The WTRU may send a sensing CSI report (e.g., via the uplink data channel or control channel). The sensing CSI report may show the determined set of PMIs and sensing performance values ​​for each configured resource set. For example, the sensing CSI report may include a set of sensing codebook entries for each resource set whose sensing performance satisfies the conditions set in the previous step, either on a broadband or subband basis. The sensing CSI report may include their corresponding post-detection SNR and sensing MMSE values. The sensing CSI report may include a representation of those resource sets for which sensing codebook entries cannot be obtained, for example, because the SNR is too low and / or the SNR variation is insufficient to reliably calculate the sensing MMSE.

[0193] Figure 8 is a flowchart of an exemplary method 800 for sensing CSI acquisition by a WTRU. Method 800 can be implemented by any combination of the WTRU's processor, memory, and transceiver. It should be understood that the exemplary sensing CSI acquisition method 800 may include one or more of the following: In 802, the WTRU may send capability information messages about the sensing CSI measurements it supports. For example, the WTRU may send a message to the network indicating one or more CSI measurements supported by the WTRU (as described herein, for example).

[0194] In 804, the WTRU may receive configuration information about the spatial characteristics of the sensing beam and the measurement and reporting of the sensing CSI. For example, the WTRU may be configured to measure and report the sensing CSI across a set of sensing TCI states, including a first set of RSs for sensing CSI acquisition defined by signal type, number of ports, resource set, periodicity, etc.; sensing performance metrics for selecting the sensing PMI (e.g., sensing MMSE, post-detection SNR, RSRP, etc.); and / or information about the sensing CSI report (e.g., content, periodicity, broadband / subband reporting mode, etc.).

[0195] In 806, the WTRU may receive a first set of RSs for sensing CSI acquisition and obtain channel responses in the resource set. For example, the WTRU may receive multiple RSs (e.g., each of multiple RSs may be associated with a configured resource set). The WTRU may receive a first set of RSs for sensing CSI acquisition across one or more resource sets and obtain sensing CSI information by at least one of the following steps: The WTRU may estimate channel responses and obtain equalized RS symbols and their post-detection SNRs. The WTRU may multiply the equalized RS symbols by a set of precoding matrices contained in the sensing codebook.

[0196] In 808, the WTRU can be obtained by, for example, removing the influence of the channels and multiplying them by N precoding matrices (e.g., those included in the sensing codebook) to obtain the equalized RS symbols.

[0197] In 810, the WTRU may obtain broadband / subband sensing performance values ​​for each precoded signal vector and resource set. The WTRU may obtain broadband or subband sensing performance values ​​for each precoded vector and resource set, and the broadband value may be obtained depending on one of the following: the average, maximum, or minimum of the subband individual values; an effective AWGN channel with the same virtual BLER performance as the actual channel; and / or a broadband value corresponding to a vector Gaussian channel obtained by considering the actual channel response in the subband. In some examples, the WTRU may determine sensing performance values ​​for each configured resource set associated with the RS (e.g., each of the configured resource sets) based on the MI associated with the RS.

[0198] In 812, the WTRU may determine a set of codebook entries using sensing performance within a specified range and / or sensing MMSE below a threshold. The WTRU may compare sensing performance values ​​to a specified range (e.g., MMSE below a threshold) and determine a subset of sensing PMI values ​​that meet the performance criteria for each resource set. Thus, the WTRU may determine the set of PMIs for a configured resource set based on the sensing performance values ​​of the configured resource set.

[0199] In 814, the WTRU may send a sensing CSI report for each resource set, including, for example, sensing codebook entries, post-detection SNR, sensing MMSE, etc. The WTRU may also send a sensing CSI report for each resource set, including, for example, a subset of sensing PMI (in the form of broadband or subband), post-detection SNR, sensing MMSE values, etc.

[0200] At 816, the WTRU may determine whether the stopping condition is met. If the WTRU at 816 determines that the stopping condition is met, method 800 terminates at 818.

[0201] Alternatively, if the WTRU determines at 816 that the stopping condition is not met, method 800 returns to 806, and the WTRU may receive another set of RS for sensing CSI acquisition and acquire channel responses on the resource set. The WTRU may repeat the steps of method 800 until the stopping condition is met, such as after an aperiodic CSI report or when a periodic or semi-periodic sensing CSI report is deactivated by (e.g., MAC CE or DCI).

[0202] Bistatic and multistatic sensing can be implemented. For example, a method and procedure for performing measurements by a WTRU for bistatic and multistatic sensing on a second set of sensing RS received from a TRP or a second WTRU.

[0203] WTRU can be configured to measure, display, or determine one or more bistatic or multistatic sensing measurement results.

[0204] The WTRU may obtain configuration information for bistatic or multistatic sensing comprising: (i) a second set of sensing RS resources for performing bistatic or multistatic measurements transmitted in a periodic, aperiodic, or semi-persistent manner; (ii) information about the sensing report; (iii) the ToA of the LOS component between the TRP and the WTRU; and / or (iv) at least one of the time intervals or predefined time intervals for performing sensing measurements, specified as, for example, start and end times or time duration (e.g., number of slots, absolute time units, etc.).

[0205] The second set of sensing RS resources may be defined as one or more of the following: (a) signals used to perform sensing measurements, including positioning signals (e.g., DL PRS, UL SRS for positioning, etc.) and / or dedicated sensing signals; (b) if any, the start RE, number of RBs, number of symbols and slots, comb size and comb offset, and / or (c) in the case of periodic and semi-periodic RS for sensing, their periodicity with respect to the number of slots, frames, time duration, etc.

[0206] Information about the sensing report may include whether the sensing report is aperiodic, periodic, or semi-permanent, and, in the latter two cases, an indication of its periodicity (e.g., with respect to the number of slots, duration, etc.).

[0207] Information in the sensing report may include sensing measurement results per MPC up to the specified or pre-configured maximum number of MPCs. For example, the sensing report may include AoA, ToA, RSRP, SNR, RTT, sensing MMSE, sensing MSE, etc.

[0208] Information about the sensing report may include one or more thresholds for successful detection of scatterers, including at least one of the following: minimum RSRP, minimum SNR, maximum sensing MMSE, maximum sensing MSE, etc.

[0209] Information in the sensing report may include, for scatterers detected by the WTRU, an indication of whether the scatter's location, velocity, or both should be reported.

[0210] The WTRU may receive a subset of active states for sensing, representing active beams for which bistatic / multistatic sensing by the WTRU is intended (e.g., in the form of active TCI states for sensing). Active TCI states for sensing may comprise a subset of available states for sensing, configured for the WTRU (e.g., via RRC IE, DCI signaling, MAC CE, etc.). A subset of active TCI states may be indicated to the WTRU via dynamic signaling (e.g., DCI, MAC CE, etc.).

[0211] Figure 9 is a system diagram 900 of an exemplary bistatic sensing measurement performed by a WTRU, supported by a sensing RS across one or more active TCI states of sensing. The WTRU may be a first WTRU receiving signals from the TRP, or a second WTRU intended to perform bistatic or multistatic sensing measurements. The WTRU may receive a second set of sensing RSs corresponding to one or more active sensing states. The WTRU may perform one or more sensing measurements supported by the second set of sensing RSs across one or more active sensing states, up to the maximum number of MPCs, either per MPC or for a subset of MPCs, including AoA, ToA, RSRP, RTT, sensing MMSE, sensing MSE, etc. The WTRU may determine the location, velocity, or both of the identified scatterers on a configuration-by-configuration basis based on the sensing measurement results.

[0212] The WTRU may transmit bistatic / multistatic sensing reports, for example, via an uplink data channel or control channel (e.g., PUCCH, PUSCH, etc.). The sensing report may include measured and estimated values ​​of sensing quantities configured up to the maximum number of MPCs for each MPC. The measured and estimated values ​​may include at least one of the measured sensing quantities, including ToA, RTT, AoA, RSRP, SNR, etc., for each active state for sensing (e.g., active TCI state for sensing). The measured and estimated values ​​may include sensing MSE, sensing MMSE, or both, for each active state for sensing. The measured and estimated values ​​may include at least one of the identified scatterer's position, velocity, or both.

[0213] Measurement results and estimates may be reported for each MPC, or for a subset of MPCs, up to the maximum number of MPCs given by the configuration or predefined by the embodiment.

[0214] WTRU may avoid reporting sensing measurements performed on any multipath components that are likely to be in a LOS state (for example, if its ToA matches the ToA of an LOS component received from the network as part of the configuration).

[0215] Based on its configuration, the WTRU may report the location of the identified scatter, the velocity of the identified scatter, and / or both, based on the sensing measurement results. The WTRU may also report (e.g., report only) the sensing measurement results (e.g., AoA, ToA, sensing MMSE, etc.).

[0216] If the sensing accuracy does not meet a pre-configured or embodiment-defined minimum threshold, the WTRU may discard the corresponding measurement result and, for example, include a notice in the report regarding insufficient sensing accuracy.

[0217] The WTRU may repeat the above steps until the termination conditions are met, such as after a non-periodic report and when periodic or semi-periodic sensing reports are deactivated by (e.g., MAC CE or DCI).

[0218] Figure 10 is a flowchart illustrating an exemplary bistatic / multistatic sensing and reporting method 1000 using a WTRU. Method 1000 can be implemented by any combination of the WTRU's processor, memory, and transceiver. It should be understood that the exemplary bistatic / multistatic sensing and reporting method 1000 may include one or more of the following:

[0219] In 1002, the WTRU may receive configuration information associated with sensing measurements and / or reporting, including a second set of sensing RS resources, a sensing report, a ToA of LOS components, and / or a time interval. The WTRU may be configured to measure and report bistatic or multistatic sensing measurement results, including a second set of sensing RS resources for bistatic or multistatic measurements, defined by one of the following: signal type, number of ports, resource set, periodicity, etc.; information about the sensing report, e.g., its content, periodicity, broadband / subband reporting mode, threshold for detecting scatterers, etc.; a ToA of LOS components; and / or a time interval for performing the sensing measurement.

[0220] In 1004, the WTRU may receive a subset of active states for sensing (e.g., active TCI states for sensing), which are indicated by, for example, MAC CE or DCI.

[0221] In 1006, the WTRU may receive a second set of sensing RS across one or more active sensing states and perform sensing measurements.

[0222] In 1008, the WTRU may send a bistatic or multistatic sensing report, including the sensing quantity and sensing MMSE for each active sensing state. For example, the WTRU may send a bistatic / multistatic sensing report, which may include any of the following: the measured quantity, position and / or velocity for each MPC or a subset of MPCs up to the maximum number of MPCs; sensing MSE, sensing MMSE, or both; and / or an indication of whether the sensing accuracy meets a pre-configured threshold.

[0223] At step 1010, the WTRU may determine whether the stopping condition is met. If the WTRU at step 1010 determines that the stopping condition is met, method 1000 terminates at step 1012. Alternatively, or in addition, if the WTRU at step 1010 determines that the stopping condition is not met, method 1000 returns to step 1004, where the WTRU receives a subset of active states for sensing (e.g., an active TCI state for sensing), which are indicated by, for example, MAC CE or DCI.

[0224] WTRU can evaluate appropriate metrics for the amount of information being sensed by a CSI. WTRU can propose criteria for determining the optimal spatial orientation to obtain the best possible sensing accuracy. WTRU can implement procedures for measuring and reporting the amount of information being sensed by a CSI. WTRU can implement bistatic and multistatic sensing procedures based on the amount of information being sensed by a CSI.

[0225] The spatial orientation of sensing can be discretized in the codebook of the sensing precoding matrix. During the sensing CSI acquisition and reporting phase, a codebook entry representing the orientation for which sensing accuracy is best possible can be selected and reported by the WTRU, with the assistance of a first RS for sensing CSI acquisition, which may be transmitted in periodic, aperiodic, or semi-periodic mode as part of sensing PMI feedback. The reported sensing PMI value may point to one or more sensing beams within the set of available TCI states configured for sensing. Sensing performance can be evaluated by the WTRU for different codebook entries based on specific performance criteria, e.g., sensing MMSE, to ensure that sensing PMI is reported in periodic, aperiodic, or semi-periodic mode until a stopping criterion is met.

[0226] During the sensing phase, the WTRU may consist of a subset of active TCI states for sensing, which may be dynamically activated, for example, by MAC CE or DCI. A second RS for sensing may be received by the WTRU for bistatic / multistatic measurements of the configured subset of active TCI states. Sensing reports may be transmitted by the WTRU in periodic, aperiodic, or semi-persistent modes, including sensing measurement results or scatter position / velocity information, until the stop conditions are met.

Claims

1. A wireless transceiver / receiver unit (WTRU), A message is sent to the network, and the message indicates one or more channel status information (CSI) measurements supported by the WTRU. It receives multiple reference signals (RS), and the multiple RS are associated with multiple configured resource sets. Based on the mutual information (MI) associated with the plurality of RSs, the respective sensing performance values ​​for each of the configured resource sets associated with the plurality of RSs are determined. Based on the respective sensing performance values ​​for each of the configured resource sets, a set of precoding matrix indicators (PMIs) is determined for each of the configured resource sets. For each of the configured resource sets, a sensing report is sent showing the respective PMI set and the respective sensing performance value. Processor configured in such a way A WTRU characterized by having the following features.

2. The aforementioned processor, The system receives configuration information including the spatial characteristics of the multiple RSs. The WTRU according to claim 1, further characterized by being configured as follows.

3. The WTRU according to claim 1, characterized in that the set of PMIs is determined based on the fact that the sensing performance values ​​for each configured resource set are within a predetermined range.

4. The WTRU according to claim 1, characterized in that the message includes an indication of 1) a performance metric supported for bistatic or multistatic sensing, or 2) a sensing codebook supported by the WTRU.

5. The WTRU according to claim 4, wherein the supported performance metrics for bistatic or multistatic sensing include least mean squares error (MMSE), signal-to-noise ratio (SNR), reference signal received power (RSRP), mean square root (RMS) error of distance estimation, RMS error of angle of arrival (AoA) estimation, RMS error of phase estimation, or RMS error of velocity estimation.

6. The WTRU according to claim 1, characterized in that the sensing performance value includes a least mean squared error (MMSE) value that is below a threshold.

7. The WTRU according to claim 1, characterized in that the sensing performance value includes a mean squared error (MSE) value that is below a threshold.

8. The WTRU according to claim 1, wherein the MI is a metric that characterizes the amount of information carried by the channels associated with each of the configured resource sets.

9. The WTRU according to claim 1, characterized in that the sensing report includes a sensing codebook index for each Channel State Information (CSI) RS Resource Indicator (CRI).

10. The WTRU according to claim 1, characterized in that the sensing performance value of the configured resource set represents the statistical error associated with the sensing metric measured for the configured resource set.

11. A method performed by a wireless transceiver unit (WTRU), Sending a message to the network, wherein the message indicates one or more channel status information (CSI) measurements supported by the WTRU, The system receives multiple reference signals (RS), the multiple RSs being associated with multiple configured resource sets, Based on the mutual information (MI) associated with the plurality of RSs, the sensing performance value for each of the configured resource sets associated with the plurality of RSs is determined. Based on the respective sensing performance values ​​for each of the configured resource sets, a set of precoding matrix indicators (PMIs) is determined for each of the configured resource sets. To send a sensing report to each of the configured resource sets, indicating the respective PMI set and the respective sensing performance value. A method characterized by comprising:

12. Receiving configuration information including the spatial characteristics of the multiple RSs The method according to 11, further comprising:

13. The method according to 11, characterized in that the set of PMIs is determined based on the fact that the sensing performance values ​​for each configured resource set are within a predetermined range.

14. The method according to 11, characterized in that the message includes an indication of 1) a performance metric supported for bistatic or multistatic sensing, or 2) a sensing codebook supported by the WTRU.

15. The method according to 14, wherein the supported performance metrics for bistatic or multistatic sensing include least mean squares error (MMSE), signal-to-noise ratio (SNR), reference signal received power (RSRP), mean square root (RMS) error of distance estimation, RMS error of angle of arrival (AoA) estimation, RMS error of phase estimation, or RMS error of velocity estimation.

16. The method according to 11, characterized in that the sensing performance value includes a least mean squared error (MMSE) value that is below a threshold.

17. The method according to 11, characterized in that the sensing performance value includes a mean squared error (MSE) value that is below a threshold.

18. The method according to 11, characterized in that the MI is a metric that characterizes the amount of information carried by the channels associated with each of the configured resource sets.

19. The method according to 11, characterized in that the sensing report includes a sensing codebook index for each Channel State Information (CSI) RS Resource Indicator (CRI).

20. The method according to 11, characterized in that the sensing performance value of the configured resource set represents the statistical error associated with the sensing metric measured for the configured resource set.

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