DIFFERENTIAL doppler BASED RF SENSING

Abstract

An example method performed by a server for frequency of arrival difference (FDOA)-based sensing for a transmitting device, the method comprising: transmitting an FDOA-based sensing configuration to the transmitting device, wherein the FDOA-based sensing configuration configures the transmitting device to transmit a first radio frequency (RF) signal, a second RF signal, and a third RF signal at a first point in time, a second point in time, and a third point in time, respectively. The method further includes obtaining a first FDOA measurement determined based on a reflection of the first RF signal and a reflection of the second RF signal and a second FDOA measurement determined based on the reflection of the second RF signal and a reflection of the third RF signal. The method further includes obtaining Doppler information of the reflector; and obtaining Doppler information of the transmitting device based on the first FDOA measurement and the second FDOA measurement and the Doppler information of the reflector.

Description

Background Art 1. Technical Field

[0002] The present disclosure generally relates to the field of wireless communication and, more particularly, to using radio frequency (RF) signals to determine Doppler information of a target.

[0003] 2. Description of the Related Art

[0004] Sensing of a target (e.g., an RF device or an object capable of reflecting RF signals) can have a wide range of consumer, industrial, commercial, military, and other applications. Different from time difference of arrival (TDOA)-based sensing, frequency difference of arrival (FDOA)-based sensing determines Doppler information of a target based on the Doppler drift of an RF signal caused by the difference between the receiver speed and the transmitter speed. Summary of the Invention

[0005] An example method for FDOA-based sensing of a transmitting device performed by a server includes: sending an FDOA-based sensing configuration to the transmitting device, where the FDOA-based sensing configuration configures the transmitting device to: send a first radio frequency (RF) signal at a first time point; send a second RF signal at a second time point; and send a third RF signal at a third time point. The method further includes: obtaining a first FDOA measurement determined based on the reflection of the first RF signal and the reflection of the second RF signal and a second FDOA measurement determined based on the reflection of the second RF signal and the reflection of the third RF signal, where the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at a receiving device. The method further includes: obtaining Doppler information of the reflector; and obtaining Doppler information of the transmitting device based on the first FDOA measurement, the second FDOA measurement, and the Doppler information of the reflector.

[0006] An example method for FDOA-based sensing of a transmitting device performed by a receiving device includes: receiving, at a first time point, a reflection of a first radio frequency (RF) signal sent by the transmitting device; and receiving, at a second time point, a reflection of a second RF signal sent by the transmitting device. The method further includes: receiving, at a third time point, a reflection of a third RF signal sent by the transmitting device; and determining a frequency offset of the reflections of the first RF signal, the second RF signal, and the third RF signal. The method further includes: determining a first FDOA measurement determined based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal and a second FDOA measurement determined based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

[0007] An example server for target sensing based on frequency difference of arrival (FDOA) includes a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors are configured to: send an FDOA-based sensing configuration to the sending device, wherein the FDOA-based sensing configuration configures the sending device to: send a first radio frequency (RF) signal at a first time point; send a second RF signal at a second time point; and send a third RF signal at a third time point. The one or more processors are further configured to: obtain a first FDOA measurement determined based on reflections of the first RF signal and reflections of the second RF signal, and a second FDOA measurement determined based on the reflections of the second RF signal and reflections of the third RF signal, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at a receiving device. The one or more processors are further configured to: obtain Doppler information of the reflector; and obtain Doppler information of the sending device based on the first FDOA measurement, the second FDOA measurement, and the Doppler information of the reflector.

[0008] An example device for target sensing based on frequency difference of arrival (FDOA) includes a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors are configured to: receive a reflection of a first radio frequency (RF) signal sent by the sending device at a first time point; and receive a reflection of a second RF signal sent by the sending device at a second time point. The one or more processors are further configured to: receive a reflection of a third RF signal sent by the sending device at a third time point; and determine a frequency offset of the reflections of the first RF signal, the second RF signal, and the third RF signal. The one or more processors are further configured to: determine a first FDOA measurement determined based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal, and a second FDOA measurement determined based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

[0009] The foregoing and other features and examples will be described in more detail in the following specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is an illustration of a communication / location / sensing system according to one embodiment.

[0011] Figure 2 is a diagram of a fifth generation new radio (5G NR) network according to an embodiment.

[0012] Figure 3 is a diagram showing the geometry and associated terms of an example of FDOA-based sensing.

[0013] Figure 4 is a diagram showing an example of oscillator error in frequency offset measurement of FDOA-based sensing and associated terms.

[0014] Figure 5 is a diagram showing an example and associated geometry of how improved FDOA-based sensing for sensing a target can be performed according to some embodiments.

[0015] Figure 6 is a flowchart illustrating how improved FDOA-based sensing for sensing a target can be performed in a bistatic setup according to some embodiments.

[0016] Figure 7 is a diagram showing an example of how improved FDOA-based sensing for sensing a target can be performed in a multistatic setup according to some embodiments.

[0017] Figure 8 is a diagram showing an example of how improved FDOA-based sensing for sensing a transmitting device can be performed according to some embodiments.

[0018] Figure 9 is a flowchart illustrating how improved FDOA-based sensing for sensing a transmitting device can be performed according to some embodiments.

[0019] Figure 10 is a method for improved FDOA-based sensing of a target performed by a transmitting device according to some embodiments.

[0020] Figure 11 is a method for improved FDOA-based sensing of a target performed by a server according to some embodiments.

[0021] Figure 12 is a method for improved FDOA-based sensing of a transmitting device performed by a transmitting device according to some embodiments.

[0022] Figure 13 is a method for improved FDOA-based sensing of a transmitting device performed by a server according to some embodiments.

[0023] Figure 14 is a block diagram of an embodiment of a computer system that can be utilized in the embodiments described herein.

[0024] Figure 15FIG. 0 is a block diagram of an embodiment of a base station that can be utilized in embodiments as described herein.

[0025] Like reference symbols in the various figures indicate like elements according to certain examples of embodiments. Additionally, multiple instances of an element can be indicated by adding a letter or a hyphen and a second number after the first number of the element. For example, multiple instances of element 110 can be indicated as 110-1, 110-2, 110-3, etc. or 110a, 110b, 110c, etc. When only the first number is used to refer to such an element, it should be understood that any instance of the element (e.g., element 110 in the previous example will refer to elements 110-1, 110-2, and 110-3 or to elements 110a, 110b, and 110c). DETAILED DESCRIPTION

[0026] The following description is for certain embodiments for the purpose of describing innovative aspects of the embodiments. However, those of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described embodiments can be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to any communication standard, such as any one of the following: Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard for ultra-wideband (UWB), IEEE 802.11 standards (including the standards identified as technologies), standards, code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile Communications (GSM), GSM / General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband CDMA (W-CDMA), Evolution-Data Optimized (EV-DO), 1xEV-DO, EV-DO Revision A, EV-DO Revision B, High Rate Packet Data (HRPD), High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Evolution High Speed Packet Access (HSPA+), Long Term Evolution (LTE), Advanced Mobile Phone System (AMPS), or other known signals for communication within a wireless, cellular, or Internet of Things (IoT) network (such as a system utilizing technologies of 3G, 4G, 5G, 6G, or their further embodiments).

[0027] As used herein, an "RF signal" includes an electromagnetic wave that transmits information through the space between a transmitter (or transmitting device or emitter) and a receiver (or receiving device). As used herein, a transmitter may send a single "RF signal" or multiple "RF signals" to a receiver. However, due to the propagation characteristics of each RF signal through multiple channels or paths, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal.

[0028] Additionally, unless otherwise specified, references to "reference signal", "positioning reference signal", "reference signal for positioning", etc. may be used to refer to signals used for positioning a user equipment (UE). As described in more detail herein, such signals may include any of a variety of signal types, but may not necessarily be limited to positioning reference signals (PRSs) as defined in relevant wireless standards.

[0029] Furthermore, unless otherwise specified, the terms "sensing" and / or "positioning" as used herein may refer to absolute position determination, relative position determination, ranging, or a combination thereof. For the purposes of position or sensing services, such sensing and / or positioning may include and / or be based on timing, angle, phase, or power measurements, or a combination thereof (which may include RF sensing measurements). Additionally or alternatively, sensing as used herein may also refer to Doppler information determination (e.g., motion determination).

[0030] Time difference of arrival (TDOA) and frequency difference of arrival (FDOA) based measurements are often used for target sensing. TDOA is related to the distance between the transmitter and the receiver, while FDOA is caused by the Doppler shift of the signal, which is due to the difference between the receiver velocity and the transmitter velocity. However, the non-linearity of the FDOA equation and the corresponding complex geometry have led to far less research on FDOA than in the case of TDOA. Although FDOA measurements are often used as an additional constraint on TDOA-based methods, in practice, there are cases where it is desirable to solve for the transmitter position using only FDOA. For example, in the case of narrowband signals with long pulse durations, the Doppler resolution is higher than the range resolution, and it may be difficult to accurately measure TDOA. Additionally, FDOA-based sensing may estimate Doppler information (e.g., motion) of the target in addition to positioning. FDOA-based sensing may also avoid error accumulation caused by Doppler shift.

[0031] As will be discussed in detail below, when determining FDOA measurements, the measured frequency offset includes not only Doppler drift but also sometimes significant oscillator errors from both the transmitter and the receiver. In particular, when using a user equipment (UE) as the receiving device (e.g., a device that receives an RF signal and measures the frequency offset), since the oscillators used by the UE are generally not temperature-controlled, the oscillator errors introduced by the receiver in the generated frequencies are non-negligible and vary throughout the day according to temperature.

[0032] The technical solutions disclosed herein provide improved FDOA-based sensing that can obtain an accurate Doppler drift estimate by removing the estimation bias caused by UE oscillator errors from the frequency offset estimate.

[0033] Figure 1 FIG. 1 is a simplified illustration of a wireless system capable of communication, positioning, and sensing according to one embodiment, which is referred to herein as the “communication / location / sensing system” 100, where the mobile device 105, the network function server 160, and / or other components of the communication / location / sensing system 100 may use the techniques provided herein for RF sensing. (That is, the embodiments are not necessarily limited to such a system.) The techniques described herein may be implemented by one or more components of the communication / location / sensing system 100. The communication / location / sensing system 100 may include a mobile device 105; one or more satellites 110 (also referred to as space vehicles (SVs)), which may include global navigation satellite system (GNSS) satellites (e.g., satellites of the Global Positioning System (GPS), GLONASS, Galileo, Beidou, etc.) and / or non-terrestrial network (NTN) satellites; a base station 120; an access point (AP) 130; a network function server 160; a network 170; and an external client 180. Generally, the communication / location / sensing system 100 may be capable of enabling communication between the mobile device 105 and other devices, positioning of the mobile device 105 and / or other devices, RF sensing performed by the mobile device 105 and / or other devices, or a combination thereof. For example, the communication / location / sensing system 100 may estimate the position of the mobile device 105 based on RF signals received by and / or transmitted from the mobile device 105 and the known positions of other components that send and / or receive RF signals (e.g., GNSS satellites 110, base station 120, AP 130). Additionally or alternatively, wireless devices such as the mobile device 105, the base station 120, and the satellite 110 (and / or other NTN platforms that may be implemented on an aircraft, a drone, a balloon, etc.) may be used to perform positioning (e.g., positioning of one or more wireless devices) and / or perform RF sensing (e.g., RF sensing of one or more objects using RF signals transmitted by one or more wireless devices).

[0034] It should be noted that Figure 1 only generalized examples of various components are provided, any or all of which may be utilized as appropriate, and each component may be repeated as needed. Specifically, although only one mobile device 105 is illustrated, it should be understood that many UEs (e.g., hundreds, thousands, millions, etc.) may utilize the communication / location / sensing system 100. Similarly, the communication / location / sensing system 100 may include more or fewer numbers of base stations 120 and / or APs 130 than those illustrated in Figure 1 . The illustrated connections that connect the various components in the communication / location / sensing system 100 include data and signaling connections, which may include additional (intermediate) components, direct or indirect physical and / or wireless connections, and / or additional networks. In addition, the components may be rearranged, combined, separated, replaced, and / or omitted depending on the desired functionality. In some embodiments, for example, the external client 180 may be directly connected to the network function server 160. Those of ordinary skill in the art will recognize many modifications to the illustrated components.

[0035] Depending on the desired functionality, the network 170 may include any one of a variety of wireless and / or wired networks. The network 170 may include, for example, any combination of public and / or private networks, local area networks and / or wide area networks, etc. In addition, the network 170 may utilize one or more wired and / or wireless communication technologies. In some embodiments, the network 170 may include, for example, a cellular or other mobile network, a wireless local area network (WLAN), a wireless wide area network (WWAN), and / or the Internet. Examples of the network 170 include long term evolution (LTE) wireless networks, fifth generation (5G) wireless networks (also referred to as new radio (NR) wireless networks or 5G NR wireless networks), Wi-Fi WLAN, and the Internet. LTE, 5G, and NR are wireless technologies defined or being defined by the Third Generation Partnership Project (3GPP). In an LTE, 5G, or other cellular network, the mobile device 105 may be referred to as a user equipment (UE). The network 170 may also include more than one network and / or more than one type of network.

[0036] Base station 120 and access point (AP) 130 are communicatively coupled to network 170. In some embodiments, base station 120 may be owned, maintained, and / or operated by a cellular network provider and may employ any one of a variety of radio technologies, as described below. Depending on the technology of network 170, base station 120 may include a Node B, evolved Node B (eNodeB or eNB), transceiver base station (BTS), radio base station (RBS), NR Node B (gNB), next-generation eNB (ng-eNB), etc. In the case where network 170 is a 5G network, base station 120 as a gNB or ng-eNB may be part of a next-generation radio access network (NG-RAN) that can be connected to a 5G core network (5GC). Given the open radio access network (O-RAN) and / or virtualized radio access network (V-RAN or vRAN) in 5G or later networks, the functions performed by base station 120 in earlier networks (e.g., 3G and 4G) may be divided into different functional components (e.g., radio unit (RU), distributed unit (DU), and central unit (CU)) and layers (e.g., L1 / L2 / L3), which may be performed on different devices at different locations connected, for example, via fronthaul connections, midhaul connections, and backhaul connections. As mentioned herein, a "base station" (or ng-eNB, gNB, etc.) may include any one or all of these functional components. For example, AP 130 may include a Wi-Fi AP or an AP or an AP with cellular capabilities (e.g., 4G LTE and / or 5G NR). Thus, mobile device 105 can communicate with network-connected devices (such as network function server 160) by accessing network 170 via base station 120 using first communication link 133 to transmit and receive information. Additionally or alternatively, since AP 130 can also be communicatively coupled to network 170, mobile device 105 can communicate with network-connected and Internet-connected devices (including network function server 160) using second communication link 135 or via one or more other mobile devices 145.

[0037] As used herein, the term "base station" generally may refer to a single physical transmission point or multiple co-located physical transmission points that may be located at base station 120. A transmission and reception point (TRP) (also referred to as a transmit / receive point) corresponds to this type of transmission point, and the term "TRP" may be used interchangeably herein with the terms "gNB", "ng-eNB", and "base station". In some cases, base station 120 may include multiple TRPs - for example, where each TRP is associated with a different antenna or different antenna array of base station 120. As used herein, the transmission function of a TRP may be performed by a transmission point (TP), and / or the reception function of a TRP may be performed by a reception point (RP), which may be physically separate or distinct from the TP. That is, a TRP may include both a TP and an RP. A physical transmission point may include an antenna array of base station 120 (e.g., as in a multiple-input multiple-output (MIMO) system and / or where beamforming is employed at the base station). In accordance with aspects of applicable 5G cellular standards, base station 120 (e.g., gNB) is capable of transmitting different "beams" in different directions and performing "beam scanning", where signals are transmitted in different directions (e.g., one after another) in different beams. The term "base station" may additionally refer to multiple non-co-located physical transmission points, which may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transmission medium) or a remote radio head (RRH) (a remote base station connected to a serving base station).

[0038] Satellite 110 can be used to localize in communication in one or more ways. For example, satellite 110 (also referred to as a space vehicle (SV)) can be part of a Global Navigation Satellite System (GNSS) such as the Global Positioning System (GPS), GLONASS, Galileo, or Beidou. Localization using RF signals from GNSS satellites can include measuring multiple GNSS signals at the GNSS receiver of mobile device 105 to perform code-based and / or carrier-based localization, which can be highly accurate. Additionally or alternatively, satellite 110 can be used for NTN-based localization, where satellite 110 can operate functionally as a transmit-receive point (TRP) (or transmit point (TP)) of a network (e.g., an LTE and / or NR network) and can be communicatively coupled to network 170. Specifically, reference signals (e.g., PRS) transmitted for NTN-based localization by satellite 110 can be similar to those transmitted by base station 120 and can be coordinated by network function server 160, which can operate as a location server. In some embodiments, the satellites 110 used for NTN-based localization can be different from those used for GNSS-based localization. In some embodiments, NTN nodes can include non-terrestrial vehicles such as airplanes, balloons, drones, etc., which can supplement or replace NTN satellites. NTN satellite 110 and / or other NTN platforms can also be utilized to perform RF sensing. As described in more detail below, the satellite can use JCS symbols in an OFDM waveform to allow for both RF sensing and communication.

[0039] The network function server 160 may include one or more servers and / or other computing devices configured to provide network management and / or network assistance functions (such as operating as a location server and / or a sensing server). For example, a location server may determine an estimated location of the mobile device 105 and / or provide data (e.g., "assistance data") to the mobile device 105 to facilitate location measurements and / or location determination by the mobile device 105. According to some embodiments, the location server may include a Home Subscriber Server (HSS) that may support the SUPL User Plane (UP) location solution defined by the Open Mobile Alliance (OMA) and may support location services for the mobile device 105 based on subscription information about the mobile device 105 stored in the location server. In some embodiments, the location server may include a Discovery SLP (D-SLP) or an Emergency SLP (E-SLP). The location server may also include an Enhanced Serving Mobile Location Center (E-SMLC) that uses a Control Plane (CP) location solution to support the location of the mobile device 105 for the LTE radio access of the mobile device 105. The location server may also include a Location Management Function (LMF) that uses a Control Plane (CP) location solution to support the location of the mobile device 105 for the NR or LTE radio access of the mobile device 105.

[0040] Similarly, the network function server 160 can be used as a sensing server. The sensing server can be used to coordinate and / or assist in coordinating the sensing of one or more objects (also referred to herein as "targets") by one or more wireless devices in the communication / location / sensing system 100. This can include the mobile device 105, the base station 120, the AP 130, other mobile devices 145, the satellite 110, or any combination thereof. A wireless device capable of performing RF sensing can be referred to herein as a "sensing node". To perform RF sensing, the sensing server can coordinate a sensing session in which one or more RF sensing nodes can perform RF sensing by transmitting RF signals (e.g., reference signals (RS)) and measuring the reflected signals or "echoes" (including the reflection of the transmitted RF signals from one or more objects / targets). For example, the reflected signals and object / target detection can be determined from the channel state information (CSI) received at the receiving device. The sensing can include (i) monostatic sensing using a single device as the transmitter (of the RF signal) and the receiver (of the reflected signal); (ii) bistatic sensing using a first device as the transmitter and a second device as the receiver; or (iii) multistatic sensing using multiple transmitters and / or multiple receivers. To facilitate sensing (e.g., in a sensing session among one or more sensing nodes), the sensing server can provide data (e.g., "assist data") to the sensing nodes to facilitate RS transmission and / or measurement, object / target detection, or any combination thereof. Such data can include an RS configuration indicating which resources (e.g., time and / or frequency resources) can be used (e.g., in the sensing session) to transmit the RS for RF sensing. According to some embodiments, the sensing server can include a sensing management function (SMF).

[0041] Although ground components such as the AP 130 and the base station 120 can be fixed, the embodiments are not limited thereto. Mobile components can be used. For example, in some embodiments, the location of the mobile device 105 can be estimated at least in part based on measurements of RF signals 140 communicated between the mobile device 105 and one or more other mobile devices 145 (the one or more other mobile devices can be mobile or fixed). As illustrated, the other mobile devices can include, for example, a mobile phone 145-1, a vehicle 145-2, a static communication / location device 145-3, or other static and / or mobile devices capable of providing wireless signals for locating the mobile device 105, or a combination thereof. The wireless signals from the mobile device 145 for locating the mobile device 105 can include using, for example (including Bluetooth Low Energy (BLE)), IEEE 802.11x (e.g., ) RF signals of Ultra-Wideband (UWB), IEEE 802.15x, or combinations thereof. The mobile device 145 can additionally or alternatively use non-RF wireless signals for the positioning of the mobile device 105, such as infrared signals or other optical technologies.

[0042] The estimated location of the mobile device 105 can be used in a variety of applications, for example, to assist the user of the mobile device 105 in direction finding or navigation or to assist another user (e.g., associated with an external client 180) in locating the mobile device 105. "Location" is also referred to herein as "location estimate", "estimated location", "position", "positioning", "positioning estimate", "position fix", "estimated positioning", "location fix", or "fix". The process of determining a location can be referred to as "positioning", "position determination", "location determination", etc. The location of the mobile device 105 can include the absolute location of the mobile device 105 (e.g., latitude and longitude and possibly altitude) or the relative location of the mobile device 105 (e.g., expressed as a distance north or south, east or west, and possibly above or below from a certain other known fixed location (including, for example, the location of the base station 120 or the AP 130) or a certain other location (such as the location of the mobile device 105 at a certain known previous time, or the location of the mobile device 145 (e.g., another UE) at a certain known previous time)). The location can be specified as a geodetic location including coordinates, which can be absolute (e.g., latitude, longitude, and optional altitude), relative (e.g., relative to a certain known absolute location), or local (e.g., X, Y, and optionally Z coordinates according to a coordinate system defined relative to a local area such as a factory, warehouse, university campus, shopping mall, stadium, or convention center). The location can alternatively be a civic location and can then include one or more of a street address (e.g., including the name or label of the country, state, county, city, road, and / or street, and / or the road or street number) and / or a label or name of a place, building, part of a building, floor of a building, and / or room within a building, etc. The location can also include an indication of uncertainty or error, such as a horizontal distance and possibly a vertical distance expected to have an error in the location, or an indication of a region or volume (e.g., a circle or an ellipse) within which the mobile device 105 is expected to be located at a certain confidence level (e.g., 95% confidence).

[0043] The external client 180 can be a web server or a remote application that can have some association with the mobile device 105 (e.g., can be accessed by the user of the mobile device 105), or can be a server, application, or computer system that provides location services to some other user or users, and the location services can include obtaining and providing the location of the mobile device 105 (e.g., to implement services such as friend or relative finding or child or pet location). Additionally or alternatively, the external client 180 can obtain the location of the mobile device 105 and provide it to emergency service providers, government agencies, etc.

[0044] As previously noted, the exemplary communication / location / sensing system 100 can be implemented using a wireless communication network such as an LTE-based or 5G NR-based network or a future 6G network. Figure 2 A diagram of a 5G NR network 200 is shown, which illustrates an implementation of a communication system (e.g., the communication / location / sensing system 100) implemented in 5G NR. The 5G NR network 200 can be configured to implement wireless communication, determine the location of a UE 205 (which can correspond to Figure 1 the mobile device 105), perform RF sensing, or a combination thereof, using access nodes that can include NR Node Bs (gNBs) 210-1 and 210-2 (collectively referred to herein as gNB 210), ng-eNB 214, and / or WLAN 216. These access nodes can use RF signaling to implement communication, implement one or more positioning methods, and / or implement RF sensing. The gNB 210 and / or ng-eNB 214 can correspond to Figure 1 the base station 120, and the WLAN 216 can correspond to Figure 1 one or more access points 130. Optionally, the 5G NR network 200 can additionally be configured to determine the location of the UE 205 to implement the one or more positioning methods by using an LMF 220 (which can correspond to the location server 160). The SMF 221 can coordinate the RF sensing of the 5G NR network 200. Here, the 5G NR network 200 includes the UE 205, as well as components of the 5G NR network, which include a Next Generation (NG) Radio Access Network (RAN) (NG-RAN) 235 and a 5G Core Network (5G CN) 240. The 5G NR network 200 can also be referred to as a 5G network and / or an NR network; the NG-RAN 235 can be referred to as a 5G RAN or an NR RAN; and the 5G CN 240 can be referred to as an NG core network. Additional components of the 5G NR network 200 are described below. The 5G NR network 200 can include additional or alternative components.

[0045] The 5G NR network 200 can also utilize information from the satellite 110. As previously indicated, the satellite 110 can include GNSS satellites from a GNSS system such as the Global Positioning System (GPS) or a similar system (e.g., GLONASS, Galileo, Beidou, Indian Regional Navigation Satellite System (IRNSS)). Additionally or alternatively, the satellite 110 can include NTN satellites that can be communicatively coupled to the LMF 220 and operatively serve as a TRP (or TP) in the NG-RAN 235. In this way, the satellite 110 can communicate with one or more gNBs 210.

[0046] It should be noted that Figure 2 Only generalized examples of various components are provided, and any or all of these various components can be utilized as the case may be, and each of these various components can be repeated or omitted as needed. Specifically, although only one UE 205 is illustrated, it should be understood that many UEs (e.g., hundreds, thousands, millions, etc.) can utilize the 5G NR network 200. Similarly, the 5G NR network 200 can include a larger (or smaller) number of satellites 110, gNBs 210, ng-eNBs 214, wireless local area networks (WLANs) 216, access and mobility management functions (AMFs) 215, external clients 230, and / or other components. The illustrated connections that connect the various components in the 5G NR network 200 include data and signaling connections, which can include additional (intermediate) components, direct or indirect physical and / or wireless connections, and / or additional networks. Additionally, the components can be rearranged, combined, separated, replaced, and / or omitted depending on the desired functionality.

[0047] The UE 205 can include and / or be referred to as a device, mobile device, wireless device, mobile terminal, terminal, mobile station (MS), secure user plane location (SUPL)-enabled terminal (SET), or some other name. Additionally, the UE 205 can correspond to a cellular phone, smartphone, laptop computer, tablet computer, personal digital assistant (PDA), navigation device, Internet of Things (IoT) device, or some other portable or mobile device. Generally, although not necessarily, the UE 205 can support wireless communication using one or more radio access technologies (RATs) such as using GSM, CDMA, W-CDMA, LTE, high rate packet data (HRPD), IEEE 802.11 Bluetooth, Worldwide Interoperability for Microwave Access (WiMAX TM )), 5G NR (e.g., using the NG-RAN 235 and the 5G CN 240), etc. The UE 205 can also support wireless communication using the WLAN 216, which (similar to one or more RATs and as previously described with respect toFigure 1 as indicated) may be connectable to other networks such as the Internet. Using one or more of these RATs may allow the UE 205 (e.g., via elements of the 5G CN 240 not shown in the figure, or possibly via a Gateway Mobile Location Center (GMLC) 225) to communicate with an external client 230 and / or allow the external client 230 (e.g., via the GMLC 225) to receive location information about the UE 205. When implemented in or communicatively coupled with a 5G NR network, Figure 2 the external client 230 may correspond to Figure 2 the external client 180. Figure 1

[0048] The UE 205 may include a single entity or may include multiple entities, such as in a personal area network where a user may employ audio, video, and / or data I / O devices, and / or body sensors, as well as separate wired or wireless modems. The estimation of the location of the UE 205 may be referred to as location, location estimation, location fixing, fixing, positioning, positioning estimation, or position fixing, and may be geodetic, providing location coordinates of the UE 205 (e.g., latitude and longitude), which may or may not include an elevation component (e.g., height above mean sea level; height above or depth below a ground plane, floor plane, or basement plane). Alternatively, the location of the UE 205 may be expressed as a civic location (e.g., a postal address or a point or small area within a building such as the name of a particular room or floor). The location of the UE 205 may also be expressed as an area or volume (defined geodetically or in civic form) within which the UE 205 is expected to be located with a certain probability or confidence level (e.g., 67%, 95%, etc.). The location of the UE 205 may also be a relative location, including, for example, distance and direction or relative X, Y (and Z) coordinates defined relative to an origin at a known location, which may be defined geodetically, in civic form, or with reference to a point, area, or volume indicated on a map, floor plan, or building plan. In the descriptions contained herein, the use of the term "location" may include any of these variants, unless otherwise indicated. When calculating the location of a UE, local X, Y, and possibly Z coordinates are typically solved for and then, if needed, the local coordinates are converted to absolute coordinates (e.g., with respect to latitude, longitude, and elevation above or below mean sea level).

[0049] Figure 2 The base stations in the NG-RAN 235 shown may correspond to Figure 1 the base stations 120 and may include gNBs 210. The paired gNBs 210 in the NG-RAN 235 may be connected to each other (e.g., as Figure 2 ​shown as a direct connection, or an indirect connection via other gNBs 210). The communication interface between base stations (gNB 210 and / or ng-eNB 214) may be referred to as the Xn interface 237. Access to the 5G network is provided to the UE 205 via wireless communication between the UE 205 and one or more of the gNBs. These gNBs may use 5G NR to provide wireless communication access to the 5G CN 240 on behalf of the UE 205. The wireless interface between the base station (gNB 210 and / or ng-eNB 214) and the UE 205 may be referred to as the Uu interface 239. 5G NR radio access may also be referred to as NR radio access or 5G radio access. In Figure 2 it is assumed that the serving gNB of the UE 205 is gNB 210-1, but other gNBs (e.g., gNB 210-2) may act as the serving gNB in the case where the UE 205 moves to another location, or may act as a secondary gNB to provide additional throughput and bandwidth to the UE 205.

[0050] Figure 2 The base stations in the NG-RAN 235 shown may additionally or alternatively include a next-generation evolved Node B (also referred to as ng-eNB) 214. The ng-eNB 214 may be connected to one or more gNBs 210 in the NG-RAN 235 - for example, directly connected, or indirectly connected via other gNBs 210 and / or other ng-eNBs. The ng-eNB 214 may provide LTE radio access and / or evolved LTE (eLTE) radio access to the UE 205. Figure 2 Some of the gNBs 210 (e.g., gNB 210-2) and / or ng-eNB 214 in may be configured to act as positioning beacons only. These positioning beacons only may send signals (e.g., positioning reference signals (PRS)) and / or may broadcast assistance data to assist in the positioning of the UE 205, but may not receive signals from the UE 205 or from other UEs. Some gNBs 210 (e.g., gNB 210-2 and / or another gNB not shown) and / or ng-eNB 214 may be configured to act as detection nodes only, and may scan for signals containing, for example, PRS data, assistance data, or other location data. Such detection nodes only may not send signals or data to the UE, but may send signals or data (relating to, for example, PRS, assistance data, or other location data) to other network entities (e.g., one or more components of the 5G CN 240, external client 230, or controller), and the other network entities may receive and store the data or use the data to locate at least the UE 205. It should be noted that while Figure 2Only one ng-eNB 214 is shown, but some embodiments may include multiple ng-eNB 214s. Base stations (e.g., gNB 210 and / or ng-eNB 214) may communicate directly with each other via the Xn communication interface. Additionally or alternatively, the base stations may communicate directly or indirectly with other components of the 5G NR network 200, such as the LMF 220 and the AMF 215.

[0051] The 5G NR network 200 may also include one or more WLANs 216, which may be connected to the non-3GPP interworking function (N3IWF) 250 in the 5G CN 240 (e.g., in the case of an untrusted WLAN 216). For example, the WLAN 216 may support IEEE 802.11 Wi-Fi access for the UE 205 and may include one or more Wi-Fi APs (e.g., Figure 1 AP130). Here, the N3IWF 250 may be connected to other elements in the 5G CN 240, such as the AMF 215. In some embodiments, the WLAN 216 may support another RAT, such as Bluetooth. The N3IWF 250 may provide support for secure access by the UE 205 to other elements in the 5G CN 240 and / or may support the interworking of one or more protocols used by the WLAN 216 and the UE 205 with one or more protocols used by other elements of the 5G CN 240, such as the AMF 215. For example, the N3IWF 250 may support: the establishment of an IPSec tunnel with the UE 205, the termination of the IKEv2 / IPSec protocol with the UE 205, the termination of the N2 and N3 interfaces to the 5G CN 240 for the control plane and the user plane, respectively, and the relay of uplink (UL) and downlink (DL) control plane non-access stratum (NAS) signaling across the N1 interface between the UE 205 and the AMF 215. In some other embodiments, the WLAN 216 may be directly connected to an element in the 5G CN 240 (e.g., the AMF 215 as shown by the dashed line in Figure 2 and without going through the N3IWF 250. For example, the direct connection of the WLAN 216 to the 5G CN 240 may occur when the WLAN 216 is a trusted WLAN for the 5G CN 240 and may be implemented using a trusted WLAN interworking function (TWIF) ( Figure 2 not shown in) that may be an element internal to the WLAN 216. It should be noted that although Figure 2 only one WLAN 216 is shown, some embodiments may include multiple WLAN 216s.

[0052] The access node may include any of a variety of network entities that enable communication between the UE 205 and the AMF 215. As noted, this may include the gNB 210, ng-eNB 214, WLAN 216, and / or other types of cellular base stations. However, an access node providing the functionality described herein may additionally or alternatively include an entity that enables communication with any one of a variety of RATs not illustrated in Figure 2 which may include non-cellular technologies. Thus, as used in the embodiments described hereinafter herein, the term "access node" may include, but is not necessarily limited to, the gNB 210, ng-eNB 214, or WLAN 216.

[0053] In some embodiments, an access node (such as the gNB 210, ng-eNB 214, and / or WLAN 216) (either alone or in combination with other components of the 5G NR network 200) may be configured to: in response to receiving a request for location information from the LMF 220, obtain location measurements of an uplink (UL) signal received from the UE 205 and / or obtain DL location measurements obtained by the UE 205 from a downlink (DL) signal received by the UE 205 from one or more access nodes. As noted, while Figure 2 the access nodes (gNB 210, ng-eNB 214, and WLAN 216) are depicted as being configured to communicate according to 5G NR, LTE, and Wi-Fi communication protocols, respectively, access nodes configured to communicate according to other communication protocols may be used, such as, for example, a Node B using the Wideband Code Division Multiple Access (WCDMA) protocol for the Universal Mobile Telecommunications Service (UMTS) Terrestrial Radio Access Network (UTRAN), an eNB using the LTE protocol for the Evolved UTRAN (E-UTRAN), or a Bluetooth beacon using the protocol for WLAN. For example, in a 4G Evolved Packet System (EPS) providing LTE radio access to the UE 205, the RAN may include the E-UTRAN, which may include base stations comprising eNBs that support LTE radio access. The core network for the EPS may include the Evolved Packet Core (EPC). The EPS may then include the E-UTRAN plus the EPC, where in Figure 2 the E-UTRAN corresponds to the NG-RAN 235 and the EPC corresponds to the 5GCN 240. The methods and techniques described herein for obtaining the civic location of the UE 205 may be applicable to such other networks.

[0054] The gNB 210 and ng-eNB 214 can communicate with the AMF 215, which communicates with the LMF 220 for positioning functions. The AMF 215 can support the mobility of the UE 205, including cell changes and handovers of the UE 205 from an access node of a first RAT (e.g., gNB 210, ng-eNB 214, or WLAN 216) to an access node of a second RAT. The AMF 215 can also participate in supporting the signaling connection with the UE 205 and possibly the data and voice bearers for the UE 205. The LMF 220 can support positioning the UE 205 using a CP location solution when the UE 205 accesses the NG-RAN 235 or WLAN 216, and can support positioning processes and methods, including UE-assisted / UE-based and / or network-based processes / methods, such as Assisted GNSS (A-GNSS), Observed Time Difference of Arrival (OTDOA) (which may be referred to as Time Difference of Arrival (TDOA) in NR), Frequency Difference of Arrival (FDOA), Real-Time Kinematics (RTK), Precise Point Positioning (PPP), Differential GNSS (DGNSS), Enhanced Cell ID (ECID), Angle of Arrival (AoA), Angle of Departure (AoD), WLAN positioning, Round-Trip Signal Propagation Delay (RTT), Multi-Cell RTT, and / or other positioning processes and methods. The LMF 220 can also process, for example, location service requests for the UE 205 received from the AMF 215 or from the GMLC 225. The LMF 220 can be connected to the AMF 215 and / or GMLC 225. In some embodiments, the network (such as the 5GCN 240) can additionally or alternatively implement other types of location support modules, such as an Evolved Serving Mobile Location Center (E-SMLC) or a SUPL Location Platform (SLP). It should be noted that in some embodiments, at least a part of the positioning functionality (including determining the location of the UE 205) can be performed at the UE 205 (e.g., by measuring the Downlink PRS (DL-PRS) signals transmitted by radio nodes such as gNB 210, ng-eNB 214, and / or WLAN 216 and / or using, for example, the assistance data provided to the UE 205 by the LMF 220).

[0055] The Gateway Mobile Location Center (GMLC) 225 can support location requests for the UE 205 received from an external client 230 and can forward such location requests to the AMF 215 for forwarding by the AMF 215 to the LMF 220. The location response from the LMF 220 (e.g., containing an estimated location of the UE 205) can be similarly returned directly or via the AMF 215 to the GMLC 225, and the GMLC 225 can then return this location response (e.g., containing the location estimate) to the external client 230.

[0056] The Network Exposure Function (NEF) 245 may be included in the 5G CN 240. The NEF 245 may support the secure exposure to external clients 230 of the capabilities and events regarding the 5G CN 240 and the UE 205, which capabilities and events may then be referred to as Access Functions (AFs) and may enable the secure provisioning of information from the external clients 230 to the 5G CN 240. The NEF 245 may be connected to the AMF 215 and / or the GMLC 225 for the purpose of obtaining the location of the UE 205 (e.g., civic location) and providing the location to the external clients 230.

[0057] As Figure 2 Further illustrated, the LMF 220 may communicate with the gNB 210 and / or with the ng-eNB 214 using the NR Positioning Protocol Annex (NRPPa) defined in 3GPP Technical Specification (TS) 38.455. NRPPa messages may be transferred between the gNB 210 and the LMF 220 and / or between the ng-eNB 214 and the LMF 220 via the AMF 215. As Figure 2 Further illustrated, the LMF 220 and the UE 205 may communicate using the LTE Positioning Protocol (LPP) defined in 3GPP TS 37.355. Here, LPP messages may be transferred between the UE 205 and the LMF 220 via the AMF 215 and the serving gNB 210-1 or serving ng-eNB 214 of the UE 205. For example, LPP messages may be transferred between the LMF 220 and the AMF 215 using service-based operation messages (e.g., based on Hypertext Transfer Protocol (HTTP)), and LPP messages may be transferred between the AMF 215 and the UE 205 using the 5G NAS protocol. The LPP protocol may be used to support positioning the UE 205 using UE-assisted and / or UE-based positioning methods such as A-GNSS, RTK, TDOA, multi-cell RTT, AoD, and / or ECID. The NRPPa protocol may be used to support positioning the UE 205 using network-based positioning methods such as ECID, AoA, uplink TDOA (UL-TDOA), and / or may be used by the LMF 220 to obtain location-related information from the gNB 210 and / or ng-eNB 214, such as parameters defining the DL-PRS transmission from the gNB 210 and / or ng-eNB 214.

[0058] In the case where the UE 205 is accessing the WLAN 216, the LMF 220 can use NRPPa and / or LPP to obtain the location of the UE 205 in a manner similar to that just described for the UE 205 accessing the gNB 210 or the ng-eNB 214. Thus, NRPPa messages can be transferred between the WLAN 216 and the LMF 220 via the AMF 215 and the N3IWF 250 to support network-based positioning of the UE 205 and / or the transfer of other location information from the WLAN 216 to the LMF 220. Alternatively, NRPPa messages can be transferred between the N3IWF 250 and the LMF 220 via the AMF 215 to support network-based positioning of the UE 205 based on location-related information and / or location measurements that are known or accessible to the N3IWF 250 and transferred from the N3IWF 250 to the LMF 220 using NRPPa. Similarly, LPP and / or LPP messages can be transferred between the UE 205 and the LMF 220 via the AMF 215, the N3IWF 250, and the serving WLAN 216 of the UE 205 to support UE-assisted or UE-based positioning of the UE 205 by the LMF 220.

[0059] As noted above, TDOA-based and FDOA-based measurements can be used to sense targets in systems such as Figure 1 the communication / location / sensing system 100 shown and / or Figure 2 the 5G NR network 200 shown. Figure 3 is a diagram of the geometry and associated terms showing an example of how existing FDOA-based sensing can be performed. Different from TDOA, FDOA measurements are caused by the Doppler shift of the signal, which is due to the difference between the receiver velocity and the transmitter velocity. Assuming the transmitter is fixed in place, the Doppler shift of the signal at receiver i is scaled by the center frequency (f0) of the transmitted signal divided by the propagation speed (c) as:

[0060]

[0061] where d i is proportional to the frequency shift of the signal at receiver i, x is the location of the transmitter, and x i is the location of the i-th receiver. The FDOA between receiver i and 1 is proportional to:

[0062]

[0063] where f0 and c are constants and are known to the system, f 1，i is the measured frequency difference. x, x1, and x iis the node location.

[0064] Based on different f's associated with multiple nodes (e.g., different receivers) 1，i (e.g., f 1，2 、f 1，3 ), location and Doppler information can be derived. For example, as Figure 3 shown, the curves 310 and 320 in plots 301 and 302 respectively show the constant FDOA for a fixed set of parameters (e.g., f 1，2 、f 1，3 ). The x - axis and y - axis in plots 301, 302, and 303 are in meters. As pointed out above, the curves 310 and 320 can identify the location x of the transmitter. For example, any intersection of the curves 310 and 320 (e.g., the intersection 330 shown in plot 303) is a potential transmitter location.

[0065] In practice, there are oscillator errors at both the transmitter and the receiver. For example, in a multistatic setup, both the transmitter and the receiver will involve two separate oscillator errors. In a monostatic setup, the oscillator errors at both the transmitter and the receiver can also be different. In particular, when using a UE (whose oscillator is typically not temperature - controlled) as the receiver, a significant error that varies throughout the day according to temperature can be introduced in the generated frequency. Therefore, the frequency offset measured by the UE includes not only the Doppler drift but also a significant oscillator error. In wireless communication, the UE modem does not attempt to distinguish the Doppler drift from the oscillator error, and the sum of the two offsets is estimated and compensated by employing a frequency tracking loop (FTL) to make the performance of the modem satisfactory. But for sensing purposes (e.g., accurately determining the movement of a target), it is important to remove the estimation bias caused by the UE oscillator error from the frequency - offset estimation in order to obtain an accurate Doppler - drift estimate.

[0066] Figure 4 is a diagram showing an example of the oscillator error in the frequency - offset measurement for FDOA - based sensing and associated terms. As Figure 4 shown, in a bistatic setup, a transmitter 410 (e.g., Figure 1 the base station 120 in Figure 1 and / or Figure 2 the gNB 210 in Figure 1 and Figure 2 the UE 105 in

[0067] and f off = f off,gNB,Tx + f off,UE,Rx

[0068] where f DL represents the downlink (DL) carrier frequency, v represents the velocity of the target, c represents the speed of light, f UE,measure represents the frequency offset measured at the UE, represents the oscillator error in the DL direction (Rx), f off，gNB，Tx represents the oscillator error from the transmitter 310, and f off,UE,Rx represents the oscillator error from the receiver 320. The target velocity component corresponding to the bistatic Doppler shift = vcosδ·cos(β / 2). The uplink (UL) process is similar to the above. As Figure 4 shown, the estimated Doppler shift includes oscillator errors associated with hardware and temperature and is sometimes difficult to accurately estimate. Therefore, an FDOA-based sensing scheme that removes / mitigates the effect of oscillator errors would be beneficial.

[0069] The technical solution disclosed herein provides improved FDOA-based sensing that can remove the estimation bias caused by UE oscillator errors from the frequency offset estimation. For example, the improved FDOA-based sensing can perform multiple measurements using the same device from a predetermined time window within which the oscillator error of the same device is constant (e.g., any oscillator error caused by environmental changes (e.g., temperature changes) will be negligible). Therefore, the accuracy of the Doppler shift estimation can be improved.

[0070] Figure 5 is a diagram showing an example of how improved FDOA-based sensing for sensing a target can be performed and the associated geometry according to some embodiments. As shown in diagram 501, a transmitter 510 (e.g., Figure 1 the base station 120 in Figure 2 and / or Figure 1 and Figure 2 the gNB 210 in Figure 1 and a receiver 520 (e.g.,

[0071] in Figure 3Unlike existing FDOA-based sensing schemes (as described) that use signals received by different receivers at the same timestamp (t1) to determine FDOA measurements, the improved FDOA-based sensing disclosed herein utilizes measurements of signals received at different timestamps (e.g., the measured frequency offsets determined at t1 and t2, respectively) to determine FDOA measurements, which reduces / mitigates oscillator errors. In some embodiments, the different timestamps can be selected from a pre-determined time window T. It should be understood that the number of timestamps is not limited to two. Increasing the number of measurements determined at different timestamps (e.g., determining more FDOA measurements based on signals transmitted at more different timestamps selected from the time window T) can increase the accuracy of the sensing results. and ) to determine FDOA measurements, which reduces / mitigates oscillator errors. In some embodiments, the different timestamps can be selected from a pre-determined time window T. It should be understood that the number of timestamps is not limited to two. Increasing the number of measurements determined at different timestamps (e.g., determining more FDOA measurements based on signals transmitted at more different timestamps selected from the time window T) can increase the accuracy of the sensing results.

[0072] As discussed, for a particular device (e.g., transmitter 510 and / or receiver 520), the oscillator error can be relatively stable within a short time window (e.g., relatively stable means that any error due to stability will be negligible). Thus, within a properly defined pre-determined window T, it is assumed that there will be a negligible change in the oscillator error for timestamps t1 and t2 within the window T. In some embodiments, the duration of the window T can be determined based on the type of the target (e.g., the speed of the target), the environment (e.g., temperature change), and / or the type of the sensing device used (e.g., the type of transmitter 510 and / or receiver 520).

[0073] According to the geometry of the improved FDOA-based sensing shown in plot 502, the FDOA of Δf 1，2 can be determined as follows:

[0074]

[0075] where is the oscillator error and can be canceled, β represents the bistatic angle (the angle subtended by the transmitter and the receiver at the target), v represents the target speed, δ represents the angle between and the target speed, and v1, δ1, β1, v2, δ2, and β2 correspond to v, δ, and β at different timestamps t1 and t2 shown in plot 502. Thus, in making multiple FDOA measurements (e.g., Δf 1，2 、Δf 1，3......), oscillator errors in the location and / or Doppler information determined based on FDOA measurements can be removed. It should be understood that the bistatic setup disclosed herein is for illustrative purposes only. For different setups (e.g., monostatic sensing or others), other suitable processes can be used.

[0076] Figure 6 is a flowchart illustrating how improved FDOA-based sensing for sensing a target can be performed in a bistatic setup in accordance with some embodiments. In some embodiments, improved FDOA-based sensing for sensing a target can be performed between a server 605, a transmitting device 610, and a sensing node 615. In some embodiments, the server 605 can correspond to Figure 1 a location server 160 (e.g., including LMF), a proprietary server, a packet controller (e.g., including a session management function (SMF)), or any other suitable server therein. The transmitting device 610 can correspond to Figure 5 a transmitter 510 therein, Figure 1 a base station 120 of Figure 2 and / or a gNB 210 of Figure 5 a receiver 520 therein and / or Figure 1 and Figure 2 a UE 105 therein. In some embodiments, the target to be sensed can correspond to Figure 1 a mobile device 145 therein or any target suitable for being sensed by FDOA-based sensing.

[0077] Starting at arrow 620, the server 605 can transmit an improved FDOA-based sensing configuration to the transmitting device 610 and the sensing node 615, which configures the transmitting device 610 and the sensing node 615 to perform improved FDOA-based sensing for sensing a target. As will be discussed in detail below, the transmission of RF signals for sensing a target can be performed according to the improved FDOA-based sensing configuration.

[0078] At block 625, an improved FDOA-based sensing may be performed between the transmitting device 610 and the sensing node 615 according to an improved FDOA-based sensing configuration. For example, in some embodiments, the transmitting device 610 may transmit multiple RF signals at different time points, such as a first RF signal at a first time point corresponding to timestamp t1, a second RF signal at a second time point corresponding to timestamp t2, a third RF signal at a third time point corresponding to timestamp t3, and so on. As discussed above, the multiple time points may be selected from a pre-determined time window T. The multiple RF signals may be reflected by the target and received by the sensing node 615. The sensing node 615 may determine the frequency offset f of the reflections of the multiple RF signals reflected by the target and received by the sensing node 615 UE,measures .

[0079] At block 630, a reporting process may be performed according to an improved FDOA-based sensing configuration. In some embodiments, the sensing node 615 may send the frequency offset to the transmitting device 610 and / or the server 605, and the transmitting device 610 and / or the server 605 may determine the FDOA measurement based on the frequency offset as disclosed above. Additionally or alternatively, the sensing node 615 may determine the FDOA measurement based on the frequency offset as disclosed above and send the FDOA measurement to the transmitting device 610 and / or the server 605. The transmitting device 610 and / or the server 605 that receives the FDOA measurement may determine the Doppler information and / or the location of the target based on the FDOA measurement. In some embodiments, the determination (e.g., the location and / or Doppler information of the target) may be shared with / transmitted to the transmitting device 610 and / or the server

[0080] During the reporting process, if the sensing node 615 is static in terms of speed and position, the speed and position of the sensing node 615 may not be repeatedly reported together with the estimated frequency offset or frequency difference. For example, the report for the measurement determined based on the RF signal transmitted at timestamp t1 may include the corresponding frequency offset (e.g., ). For example, the format of the report may be

[0081] Alternatively or additionally, if the sensing node 615 is moving, the speed and position of the sensing node 615 may also be reported together with the frequency offset. For example, the report for the measurement determined based on the RF signal transmitted at timestamp t1 may include the corresponding frequency offset, speed, and position of the sensing node 615 (e.g., ). For example, the format of the report may be

[0082] Figure 7 is a diagram illustrating an example of how improved FDOA-based sensing for sensing a target can be performed in a multi-base setup. As Figure 7 shown, a transmitter 710 (e.g., Figure 1 the base station 120 in Figure 2 and / or Figure 1 the gNB 210 in Figure 2 ) and a plurality of receivers 720 (e.g., Figure 1 the UE 105 in

[0083] and ) are jointly configured to detect a target 730 (e.g., the mobile device 145 in Figure 5 and Figure 6 ). In some embodiments, the target 730 may correspond to a vehicle, a pedestrian, or any suitable target having relative movement with respect to the transmitter 710 and / or the plurality of receivers 720.

[0084] Figure 8 is a diagram illustrating an example of how improved FDOA-based sensing for sensing a transmitting device can be performed. As Figure 5 shown, the transmitting device 810 to be sensed may correspond to the mobile device 145 (e.g., attached to a vehicle, a pedestrian, or any suitable target having relative movement with respect to the receiver 820). In some embodiments, the reflector 830 may be a reconfigurable intelligent surface (RIS), a vehicle, or any suitable object having known Doppler information (e.g., known position and velocity).

[0085] Similar to the improved FDOA - based sensing for sensing a target, here the method utilizes measurements of signals received by the receiver 820 at different time points (e.g., transmitted by the transmitting device 810, reflected by the reflector 830, and received by the receiver 820), e.g., the measured frequency offsets f UE，measure，t1 and f UE，measure，2 ) to determine the FDOA measurement. In some embodiments, the different time points may be selected from a pre - determined time window T. Increasing the number of measurements determined at different time points (e.g., determining more FDOA measurements based on signals transmitted at more different time points selected from the time window T) can increase the accuracy of the sensing results. As discussed, in some embodiments, the duration of the window T may be determined according to the type of the target (e.g., the speed of the target), the environment (e.g., the speed of temperature change), and / or the type of the sensing device used (e.g., the type of the transmitting device 810 and / or the receiver 820).

[0086] Thus, the FDOA measurement of Δf t1，t2 can be determined according to:

[0087] Δf t1,t2 = f Rx，measure，t1 - f Rx，measure，t2

[0088] In some embodiments, the improved FDOA - based sensing for sensing a transmitting device may also utilize signals received by the receiver 820 at the same time point but through different paths (e.g., reflected by different reflectors, f Rx，measure，path1 and f Rx，measure，path2 ). The FDOA of Δf t1，t2 can be determined according to:

[0089] Δf path1,path2 = f Rx，measure，path1 - f Rx，measure，path2

[0090] Figure 9 is a flowchart illustrating how the improved FDOA - based sensing for sensing a transmitting device may be performed according to some embodiments. In some embodiments, the improved FDOA - based sensing for sensing a transmitting device may be performed among the server 905, the transmitting device 910, the sensing node 915, and the reflector 920. In some embodiments, the server 905 may correspond to the location server 160 (e.g., including LMF), a proprietary server, a packet controller (e.g., including session management function (SMF)), or any other suitable server in Figure 1 . The transmitting device 910 may correspond to the transmitting device 810 in Figure 8 , Figure 1 andFigure 2 The UE 105 in Figure 1 corresponds to the mobile device 145 in, or may correspond to any target suitable for sensing by FDOA-based sensing. The sensing node 915 may correspond to Figure 1 the base station 120 of Figure 2 and / or Figure 8 the gNB 210 of. The reflector 920 may correspond to the reflector 830 in

[0091] In some embodiments, the improved FDOA-based sensing may optionally start at arrow 925, where the transmitting device 910 may send a sensing request to the server 905.

[0092] At arrow 930, the server 905 may transmit an improved FDOA-based sensing configuration to the transmitting device 910. In some embodiments, the improved FDOA-based sensing configuration configures the transmitting device 910 to sense the RF signals of the transmitting device 910.

[0093] At arrow 935, the server 905 may transmit a reporting configuration to the reflector 920, which schedules the reflector 920 to report its speed and location information to the server 905.

[0094] At arrow 940, the reflector 920 may report back its speed and location information to the server 905 according to the configuration.

[0095] At block 945, the improved FDOA-based sensing may be performed between the transmitting device 910, the sensing node 915, and the reflector 920 according to the improved FDOA-based sensing configuration. For example, in some embodiments, the transmitting device 910 may send multiple RF signals at different time points, such as sending a first RF signal at a first time point corresponding to the time stamp t1, sending a second RF signal at a second time point corresponding to the time stamp t2, sending a third RF signal at a third time point corresponding to the time stamp t3, etc. As discussed above, the multiple time stamps may be selected from a pre-determined time window T. The multiple RF signals may be reflected by the reflector 920 and received by the sensing node 915. The sensing node 915 may determine the frequency offset f of the reflections of the multiple RF signals reflected by the reflector 920 and received by the sensing node 915 UE,measures .

[0096] At block 950, a reporting process may be performed according to an improved FDOA-based sensing configuration. In some embodiments, the sensing node 915 may send a frequency offset to the server 905, and the server 905 may determine an FDOA measurement based on the frequency offset as disclosed above. Additionally or alternatively, the sensing node 915 may determine an FDOA measurement based on the frequency offset as disclosed above and send the FDOA measurement to the server 905. In some embodiments, the sensing node 915 and / or the server 905 may determine the location and Doppler information of a target (e.g., the transmitting device 910) based on the FDOA measurement. In some embodiments, the determination (e.g., the location and Doppler information of the target) may be shared with and / or sent to the sensing node 915 and / or the server.

[0097] Figure 10 is a flowchart of a method 1000 for improved FDOA-based sensing of a target performed by a transmitting device according to one embodiment. In some embodiments, the transmitting device may correspond to the transmitter 510 in Figure 5 and the transmitting device 610 in Figure 6 . Components for performing the functionality illustrated in one or more of the blocks shown in Figure 10 may be performed by hardware and / or software components of a base station. Figure 15 Example components of the base station 120 are illustrated in

[0098] At block 1010, the functionality includes: transmitting a first radio frequency (RF) signal reflected by the target at a first time point corresponding to a timestamp t1. Components for performing the functionality at block 1010 may include the bus 1505, the processor 1510, the memory 1560, the wireless communication interface 1530, and / or other components of the base station 120 as illustrated in Figure 15 .

[0099] At block 1020, the functionality includes: transmitting a second RF signal reflected by the target at a second time point corresponding to a timestamp t2. Components for performing the functionality at block 1020 may include the bus 1505, the processor 1510, the memory 1560, the wireless communication interface 1530, and / or other components of the base station 120 as illustrated in Figure 15 .

[0100] At block 1030, the functionality includes: transmitting a third RF signal reflected by the target at a third time point corresponding to a timestamp t3. Components for performing the functionality at block 1030 may include the bus 1505, the processor 1510, the memory 1560, the wireless communication interface 1530, and / or other components of the base station 120 as illustrated in Figure 15Exemplified bus 1505, processor 1510, memory 1560, wireless communication interface 1530, and / or other components of base station 120.

[0101] As noted above, in some embodiments, different time points (e.g., corresponding to timestamps t1, t2, and t3 respectively) can be selected from a predetermined time window T. In some embodiments, reflections of multiple RF signals can be received by a sensing node (e.g., Figure 6 sensing node 615 in UE,measures .

[0102] At block 1040, the functionality includes: obtaining a first FDOA measurement determined based on reflections of a first RF signal and reflections of a second RF signal, and a second FDOA measurement determined based on reflections of the second RF signal and reflections of a third RF signal, where the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a target and received at the sensing node. Components for performing the functionality at block 1040 may include Figure 15 exemplified bus 1505, processor 1510, memory 1560, wireless communication interface 1530, and / or other components of base station 120.

[0103] At block 1050, the functionality includes: obtaining Doppler information of the target determined based on the first FDOA measurement and the second FDOA measurement. For example, the Doppler information can be determined based on the first FDOA measurement and the second FDOA measurement. As disclosed above, the position and velocity of the target can be determined based on the Doppler information of the target. Components for performing the functionality at block 1010 may include Figure 15 exemplified bus 1505, processor 1510, memory 1560, wireless communication interface 1530, and / or other components of base station 120.

[0104] In some embodiments, before block 1010, method 1000 may further include: receiving, from a server, an FDOA-based sensing configuration for locating a target, wherein transmitting the first RF signal, the second RF signal, and the third RF signal is performed according to the FDOA-based sensing configuration. Accordingly, the functionality at blocks 1040 and 1050 may be performed according to the FDOA-based sensing configuration. For example, the sensing node may send a frequency offset to the transmitting device and / or the server, and the transmitting device and / or the server may determine an FDOA measurement based on the frequency offset as disclosed above. Additionally or alternatively, the sensing node may determine an FDOA measurement based on the frequency offset as disclosed above, and send the FDOA measurement to the transmitting device and / or the server. The transmitting device and / or the server that receives the FDOA measurement may determine Doppler information and / or a location of the target based on the FDOA measurement. In some embodiments, the determination (e.g., the location and / or Doppler information of the target) may be shared with and / or sent to the transmitting device and / or the server. For example, method 1000 may further include: receiving, from a server, Doppler information of the target determined based on a first FDOA and a second FDOA.

[0105] Figure 11 is a flowchart of a method 1100 for improved FDOA-based sensing of a target performed by a server according to one embodiment. In some embodiments, the server may correspond to the server 605 in Figure 6 or the location server 160 (e.g., including LMF) in Figure 1 , a proprietary server, a packet controller (e.g., including a session management function (SMF)), or any other suitable server. Components for performing the functionality illustrated in one or more of the blocks shown in Figure 11 may be executed by hardware and / or software components of a computer system. Figure 14 Example components of a computer system are illustrated in

[0106] At block 1110, the functionality includes: transmitting, to a transmitting device, an FDOA-based sensing configuration, wherein the FDOA-based sensing configuration configures the transmitting device to: transmit a first RF signal reflected by a target at a first time point corresponding to a timestamp t1; transmit a second RF signal reflected by the target at a second time point corresponding to a timestamp t2; and transmit a third RF signal reflected by the target at a third time point corresponding to a timestamp t3. Components for performing the functionality at block 1110 may include the bus 1405, the processor 1410, the memory 1435, the wireless communication interface 1433, and / or other components of the computer system 1400 as illustrated in Figure 14 .

[0107] As noted above, in some embodiments, different timestamps t1, t2, and t3 may be selected from a predetermined time window T. In some embodiments, reflections of multiple RF signals may be received by a sensing node (e.g., the sensing node 615 in Figure 6 ), and the sensing node may determine the frequency offset f of these reflections UE,measures .

[0108] At block 1120, the functionality includes: obtaining a first FDOA measurement determined based on reflections of a first RF signal and a second RF signal and a second FDOA measurement determined based on reflections of the second RF signal and a third RF signal, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a target and received at the sensing node. The components for performing the functionality at block 1120 may include the bus 1405, the processor 1410, the memory 1435, the wireless communication interface 1433, and / or other components of the computer system 1400 as Figure 14 illustrated.

[0109] At block 1130, the functionality includes: obtaining Doppler information of a target determined based on the first FDOA and the second FDOA. The components for performing the functionality at block 1130 may include the bus 1405, the processor 1410, the memory 1435, the wireless communication interface 1433, and / or other components of the computer system 1400 as Figure 14 illustrated.

[0110] In some embodiments, the functionality at block 1120 and block 1130 may be performed according to an FDOA-based sensing configuration. For example, the sensing node may send a frequency offset to a sending device and / or a server, and the sending device and / or the server may determine an FDOA measurement based on the frequency offset as disclosed above. Additionally or alternatively, the sensing node may determine an FDOA measurement based on the frequency offset as disclosed above and send the FDOA measurement to the sending device and / or the server. The sending device and / or the server that receives the FDOA measurement may determine the Doppler information and / or the location of the target based on the FDOA measurement. In some embodiments, the determination (e.g., the location and / or the Doppler information of the target) may be shared with / transmitted to the sending device and / or the server. For example, method 1100 may further include: receiving, from the sensing node, a first FDOA measurement and a second FDOA measurement determined based on reflections of a first RF signal, a second RF signal, and a third RF signal received by the sensing node.

[0111] Figure 12is a flowchart of method 1200 for improved FDOA-based sensing of a transmitting device, performed by a server according to one embodiment. In some embodiments, the transmitting device may correspond to the server 905 in Figure 9 the location server 160 (e.g., including LMF) in Figure 1 , a proprietary server, a packet controller (e.g., including session management function (SMF)), or any other suitable server. Components for performing the functionality illustrated in one or more of the boxes shown in Figure 12 may be executed by hardware and / or software components of a computer system. Figure 14 Example components of a computer system are illustrated in

[0112] At block 1210, the functionality includes: sending an FDOA-based sensing configuration to the transmitting device, where the FDOA-based sensing configuration configures the transmitting device to: transmit an RF signal at a first time point corresponding to timestamp t1; transmit a second RF signal at a second time point corresponding to timestamp t2; and transmit a third RF signal at a third time point corresponding to timestamp t3. Components for performing the functionality at block 1210 may include the bus 1405, processor 1410, memory 1435, wireless communication interface 1433, and / or other components of the computer system 1400, as illustrated in Figure 14 .

[0113] As discussed above, the multiple time points t1, t2, and t3 may be selected from a pre-determined time window T. The multiple RF signals may be reflected by a reflector (e.g., Figure 9 the reflector 920 in Figure 9 ) and received by a receiver (e.g., UE,measures the sensing node 915 in

[0114] At block 1220, the functionality includes: obtaining a first FDOA measurement determined based on the reflection of the first RF signal and the reflection of the second RF signal, and a second FDOA measurement determined based on the reflection of the second RF signal and the reflection of the third RF signal, where the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at the receiving device. Components for performing the functionality at block 1220 may include the bus 1405, processor 1410, memory 1435, wireless communication interface 1433, and / or other components of the computer system 1400, as illustrated in Figure 14 .

[0115] At block 1230, the functionality includes: obtaining Doppler information of a reflector. Components for performing the functionality at block 1230 may include the bus 1405, processor 1410, memory 1435, wireless communication interface 1433, and / or other components of the computer system 1400 as illustrated in Figure 14 .

[0116] At block 1240, the functionality includes: obtaining Doppler information of a transmitting device based on a first FDOA measurement, a second FDOA measurement, and the Doppler information of the reflector. Components for performing the functionality at block 1240 may include the bus 1405, processor 1410, memory 1435, wireless communication interface 1433, and / or other components of the computer system 1400 as illustrated in Figure 14 .

[0117] In some embodiments, blocks 1220, 1230, and 1240 may be performed according to an FDOA-based sensing configuration. For example, a receiver may send a frequency offset to a server, and the server may determine an FDOA measurement based on the frequency offset as disclosed above. Additionally or alternatively, the receiver may determine an FDOA measurement based on the frequency offset as disclosed above and send the FDOA measurement to the server. In some embodiments, the receiver and / or the server may determine the location and Doppler information of a target (e.g., a transmitting device) based on the FDOA measurement. In some embodiments, the determination (e.g., the location and Doppler information of the target) may be shared with and / or sent to the receiver and / or the server.

[0118] In some embodiments, before block 1210, method 1200 may further include: receiving, from a transmitting device, a request to perform FDOA-based sensing, wherein transmitting the FDOA-based sensing configuration is in response to receiving the request.

[0119] Figure 13 is a flowchart of a method 1300 for improved FDOA-based sensing of a transmitting device by a receiving device according to one embodiment. In some embodiments, the receiving device may correspond to the receiver 820 in Figure 8 and / or the sensing node 915 in Figure 9 . Components for performing the functionality illustrated in one or more of the blocks shown in Figure 13 may be performed by hardware and / or software components of a base station. Figure 15 Example components of the base station 120 are illustrated in

[0120] At block 1310, the functionality includes: receiving a reflection of a first radio frequency (RF) signal transmitted by a transmitting device at a first time point corresponding to timestamp t1. Components for performing the functionality at block 1310 may include a bus 1505, a processor 1510, a memory 1560, a wireless communication interface 1530, and / or other components of base station 120 as illustrated by Figure 15 etc.

[0121] At block 1320, the functionality includes: receiving a reflection of a second RF signal transmitted by a transmitting device at a second time point corresponding to timestamp t2. Components for performing the functionality at block 1320 may include a bus 1505, a processor 1510, a memory 1560, a wireless communication interface 1530, and / or other components of base station 120 as illustrated by Figure 15 etc.

[0122] At block 1330, the functionality includes: receiving a reflection of a third RF signal transmitted by a transmitting device at a third time point corresponding to timestamp t3. Components for performing the functionality at block 1330 may include a bus 1505, a processor 1510, a memory 1560, a wireless communication interface 1530, and / or other components of base station 120 as illustrated by Figure 15 etc.

[0123] As noted above, in some embodiments, the different time points (e.g., corresponding to timestamps t1, t2, and t3 respectively) may be selected from a pre - determined time window T.

[0124] At block 1340, the functionality includes: determining a frequency offset of the reflections of the first RF signal, the second RF signal, and the third RF signal. Components for performing the functionality at block 1340 may include a bus 1505, a processor 1510, a memory 1560, a wireless communication interface 1530, and / or other components of base station 120 as illustrated by Figure 15 etc.

[0125] At block 1350, the functionality includes: determining a first FDOA measurement based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal, and a second FDOA measurement based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal. Components for performing the functionality at block 1350 may include a bus 1505, a processor 1510, a memory 1560, a wireless communication interface 1530, and / or other components of base station 120 as illustrated by Figure 15 etc.

[0126] In some embodiments, prior to block 1310, method 1300 may further include: receiving, from a server, an FDOA-based sensing configuration, wherein a receiving device receives a first RF signal, a second RF signal, and a third RF signal according to the FDOA-based sensing configuration.

[0127] In some embodiments, block 1340 and block 1350 may be performed according to the FDOA-based sensing configuration. For example, a receiver may send a frequency offset to the server, and the server may determine an FDOA measurement based on the frequency offset as disclosed above. Additionally or alternatively, the receiver may determine an FDOA measurement based on the frequency offset as disclosed above, and send the FDOA measurement to the server. In some embodiments, the receiver and / or the server may determine the location and Doppler information of a target (e.g., a transmitting device) based on the FDOA measurement. In some embodiments, the determination (e.g., the location and Doppler information of the target) may be shared with and / or sent to the receiver and / or the server.

[0128] Figure 14 is a block diagram of an embodiment of a computer system 1400 that may be used, in whole or in part, to provide the functionality of one or more network components (e.g., Figures 5 to 9 and Figure 12 location server 160) as described in the embodiments herein. It should be noted that Figure 14 is only intended to provide a generalized illustration of the various components, any or all of which may be utilized as appropriate. Thus, Figure 14 broadly illustrates how individual system elements may be implemented in a relatively separated or relatively more integrated manner. Additionally, it may be noted that Figure 14 the illustrated components may be localized to a single device and / or distributed among various networked devices that may be located at different geographical locations.

[0129] Computer system 1400 is shown including hardware elements that may be electrically coupled (or communicate in other ways as appropriate) via bus 1405. The hardware elements may include a processor 1410, which may include, but is not limited to, one or more general-purpose processors, one or more dedicated processors (such as digital signal processing chips, graphics acceleration processors, etc.), and / or other processing structures that may be configured to perform one or more of the methods described herein. Computer system 1400 may also include one or more input devices 1415, which may include, but are not limited to, a mouse, a keyboard, a camera, a microphone, etc.; and one or more output devices 1420, which may include, but are not limited to, a display device, a printer, etc.

[0130] The computer system 1400 may also include one or more non-transitory storage devices 1425 (and / or communicate with the one or more non-transitory storage devices), which may include, but are not limited to, local and / or network-accessible storage, and / or may include, but are not limited to, disk drives, drive arrays, optical storage devices, solid-state storage devices (such as RAM and / or ROM), which may be programmable and / or flash-updateable, etc. Such storage devices may be configured to implement any suitable data storage, including but not limited to various file systems, database structures, etc. Such data storage may include databases and / or other data structures for storing and managing messages and / or other information to be transmitted to one or more devices via the hub, as described herein.

[0131] The computer system 1400 may also include a communication subsystem 1430, which may include wireless communication technologies managed and controlled by a wireless communication interface 1433, as well as wired technologies (such as Ethernet, coaxial communication, Universal Serial Bus (USB), etc.). The wireless communication interface 1433 may include one or more wireless transceivers, which may transmit and receive wireless signals 1455 (e.g., signals according to 5GNR or LTE) via a wireless antenna 1450. Thus, the communication subsystem 1430 may include modems, network cards (wireless or wired), infrared communication devices, wireless communication devices, and / or chip sets, etc., which may enable the computer system 1400 to communicate with any device (including user equipment (UE), base stations, and / or other TRPs, and / or any other electronic device described herein) on any or all of the communication networks described herein on the corresponding network. Thus, the communication subsystem 1430 may be used to receive and transmit data, as described in the embodiments herein.

[0132] In many embodiments, the computer system 1400 will also include a working memory 1435, which may include a RAM or ROM device, as described above. Software elements shown to be located within the working memory 1435 may include an operating system 1440, device drivers, executable libraries, and / or other code (such as one or more applications 1445), which may include computer programs provided by various embodiments, and / or may be designed to implement methods provided by other embodiments and / or configure systems provided by other embodiments, as described herein. By way of example only, one or more of the processes described with respect to the methods discussed above may be implemented as code and / or instructions executable by a computer (and / or a processor within the computer); then, in one aspect, such code and / or instructions may be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations according to the described methods.

[0133] These sets of instructions and / or code can be stored on a non-transitory computer-readable storage medium (such as the storage device 1425 described above). In some cases, the storage medium can be incorporated within a computer system such as computer system 1400. In other embodiments, the storage medium can be separate from the computer system (e.g., a removable medium such as an optical disc), and / or can be provided in the form of an installation package such that the storage medium can be used to program, configure, and / or adapt a general-purpose computer with the instructions / code stored thereon. These instructions can be in the form of executable code capable of being executed by computer system 1400, and / or can be in the form of source and / or installable code which, when compiled and / or installed on computer system 1400 (e.g., using any of a variety of commonly available compilers, installers, compression / decompression utilities, etc.), takes the form of executable code.

[0134] Figure 15 is a block diagram of an embodiment of base station 120 that can be utilized as described hereinabove (e.g., in conjunction with Figures 5 to 10 and Figure 12 ). It should be noted that Figure 15 is only intended to provide a generalization of the various components, any or all of which may be utilized as appropriate. In some embodiments, base station 120 can correspond to a gNB, an ng-eNB, and / or (more generally) a TRP.

[0135] Base station 120 is shown as including hardware elements that can be electrically coupled (or communicate in other ways as appropriate) via bus 1505. The hardware elements can include a processor 1510, which can include but is not limited to one or more general-purpose processors, one or more dedicated processors (such as DSP chips, graphics acceleration processors, ASICs, etc.), and / or other processing structures or components. As Figure 15 shown, depending on the desired functionality, some embodiments can have a separate DSP 1520. According to some embodiments, wireless communication-based location determination and / or other determinations can be provided in processor 1510 and / or wireless communication interface 1530 (discussed below). Base station 120 can also include one or more input devices, which can include but are not limited to a keyboard, a display, a mouse, a microphone, buttons, a dial pad, switches, etc.; and one or more output devices, which can include but are not limited to a display, light-emitting diodes (LEDs), speakers, etc.

[0136] Base station 120 can also include a wireless communication interface 1530, which can include but is not limited to a modem, a network card, an infrared communication device, a wireless communication device, and / or a chipset (such as Devices, IEEE 802.11 devices, IEEE 802.15.4 devices, Wi-Fi devices, WiMAX devices, cellular communication facilities, etc.), the wireless communication interface enables the base station 120 to communicate as described herein. The wireless communication interface 1530 may permit communicating (e.g., sending and receiving) data and signaling to / from UEs, other base stations / TRPs (such as eNBs, gNBs, and ng-eNBs) and / or other network components, computer systems, and / or any other electronic devices described herein. Communication may be performed via one or more wireless communication antennas 1532 that transmit and / or receive wireless signals 1534.

[0137] The base station 120 may also include a network interface 1580, which may include support for wired communication technologies. The network interface 1580 may include a modem, a network card, a chipset, etc. The network interface 1580 may include one or more input and / or output communication interfaces to permit exchanging data with a network, a communication network server, a computer system, and / or any other electronic device described herein.

[0138] In many embodiments, the base station 120 may also include a memory 1560. The memory 1560 may include, but is not limited to, local and / or network-accessible storage devices, disk drives, drive arrays, optical storage devices, solid-state storage devices (such as RAM and / or ROM), which may be programmable, flash-updatable, etc. Such storage devices may be configured to implement any suitable data storage, including but not limited to various file systems, database structures, etc.

[0139] The memory 1560 of the base station 120 may also include software elements ( Figure 15 not shown), including an operating system, device drivers, executable libraries, and / or other code (such as one or more applications), which may include computer programs provided by various embodiments, and / or may be designed to implement methods provided by other embodiments and / or configure systems provided by other embodiments, as described herein. By way of example only, one or more of the processes described with respect to the methods discussed above may be implemented as code and / or instructions in the memory 1560 executable by the base station 120 (and / or the processor 1510 or DSP 1520 within the base station 120). Then, in some embodiments, such code and / or instructions may be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the described methods.

[0140] It will be apparent to those skilled in the art that basic variations can be made in accordance with specific requirements. For example, customized hardware can also be used, and / or specific elements can be implemented in hardware, software (including portable software such as applets, etc.), or both. In addition, connections with other computing devices such as network input / output devices can be employed.

[0141] Referring to the accompanying drawings, components that may include memory may include non-transitory machine-readable media. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any storage medium that participates in providing data that causes a machine to operate in a particular manner. In the embodiments provided above, various machine-readable media may be involved in providing instructions / code to a processor and / or other devices for execution. Additionally or alternatively, the machine-readable medium may be used to store and / or carry such instructions / code. In many implementations, the computer-readable medium is a physical and / or tangible storage medium. Such media may take many forms, including but not limited to non-volatile media and volatile media. Common forms of computer-readable media include, for example: magnetic and / or optical media, any other physical media with a hole pattern, RAM, programmable ROM (PROM), erasable PROM (EPROM), FLASH-EPROM, any other memory chip or memory cartridge, or any other medium from which a computer can read instructions and / or code.

[0142] The methods, systems, and devices discussed herein are examples. Various embodiments may omit, substitute, or add various processes or components as appropriate. For example, the features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. The various components of the drawings provided herein may be embodied in hardware and / or software. Additionally, technology evolves, and thus many elements are examples that do not limit the scope of the present disclosure to those specific examples.

[0143] It has proven convenient, for commonly used reasons, to sometimes refer to such signals as bits, information, values, elements, symbols, characters, variables, items, numbers, numerals, etc. However, it should be understood that all of these or similar terms should be associated with appropriate physical quantities and are merely convenient labels. Unless specifically stated otherwise, as is apparent from the above discussion, it should be understood that throughout this specification, discussions using terms such as "processing", "computing", "calculating", "determining", "ascertaining", "identifying", "relating", "measuring", "performing", etc. refer to the actions or processes of a particular apparatus, such as a special purpose computer or similar special purpose electronic computing device. Thus, in the context of this specification, a special purpose computer or similar special purpose electronic computing device is capable of manipulating or transforming signals, typically represented as physical, electronic, electrical, or magnetic quantities in the memory, registers, or other information storage devices, transmitting devices, or display devices of the special purpose computer or similar special purpose electronic computing device.

[0144] As used herein, the terms "and" and "or" may include a variety of meanings that also are expected to depend at least in part upon the context in which such terms are used. Generally, "or" if used in connection with a list, such as A, B, or C, is intended to mean A, B, and C (here used in the inclusive sense) as well as A, B, or C (here used in the exclusive sense). Additionally, as used herein, the term "one or more" may be used to describe any feature, structure, or characteristic in the singular or may be used to describe some combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example and the claimed subject matter is not limited to this example. Further, the term "at least one of...", if used in connection with a list, such as A, B, or C, can be interpreted to mean any combination of A, B, and / or C, such as A, AB, AA, AAB, AABBCCC, etc.

[0145] Numerous embodiments have been described and various modifications, alternative constructions, and equivalent forms can be used without departing from the scope of the disclosure. For example, the above elements may be merely components of a larger system, where other rules may take precedence over the application of various embodiments or otherwise modify the application of various embodiments. Additionally, multiple steps may be performed before, during, or after considering the above elements. Accordingly, the above description does not limit the scope of the disclosure.

[0146] In view of this description, the various embodiments may include different combinations of features. Specific examples of the embodiments are described in the following numbered clauses:

[0147] Clause 1. A method for FDOA-based sensing of a transmitting device performed by a server, the method comprising: sending an FDOA-based sensing configuration to the transmitting device, wherein the FDOA-based sensing configuration configures the transmitting device to: transmit a first radio frequency (RF) signal at a first time point; transmit a second RF signal at a second time point; and transmit a third RF signal at a third time point. The method further comprises: obtaining a first FDOA measurement determined based on reflections of the first RF signal and reflections of the second RF signal and a second FDOA measurement determined based on the reflections of the second RF signal and reflections of the third RF signal, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at a receiving device. The method further comprises: obtaining Doppler information of the reflector; and obtaining Doppler information of the transmitting device based on the first FDOA measurement, the second FDOA measurement, and the Doppler information of the reflector.

[0148] Clause 2. The method according to Clause 1, the method further comprising: determining the location and velocity of the transmitting device based on the Doppler information of the transmitting device.

[0149] Clause 3. The method according to any one of Clauses 1 or 2, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

[0150] Clause 4. The method according to any one of Clauses 1 to 3, the method further comprising: receiving a request to perform the FDOA-based sensing from the transmitting device, wherein transmitting the FDOA-based sensing configuration is in response to receiving the request.

[0151] Clause 5. The method according to any one of Clauses 1 to 4, the method further comprising: obtaining a frequency offset of the reflection from the receiving device, wherein obtaining the first FDOA measurement and the second FDOA measurement further comprises: determining a frequency difference between the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal and the second FDOA measurement determined from the frequency difference between the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

[0152] Clause 6. The method according to any one of Clauses 1 to 5, wherein obtaining the Doppler information of the transmitting device further comprises: determining the Doppler information based on the first FDOA measurement and the second FDOA measurement.

[0153] Clause 7. The method according to any one of Clauses 1 to 6, wherein the reflector comprises a reconfigurable intelligent surface (RIS).

[0154] Clause 8. A method for FDOA-based sensing of a transmitting device by a receiving device, the method comprising: receiving a reflection of a first radio frequency (RF) signal transmitted by the transmitting device at a first time point; and receiving a reflection of a second RF signal transmitted by the transmitting device at a second time point. The method further comprises: receiving a reflection of a third RF signal transmitted by the transmitting device at a third time point; and determining a frequency offset of the reflections of the first RF signal, the second RF signal, and the third RF signal. The method further comprises: determining a first FDOA measurement determined based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal and a second FDOA measurement determined based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

[0155] Clause 9. The method according to Clause 8, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

[0156] Clause 10. The method according to any one of Clauses 8 or 9, the method further comprising: receiving an FDOA-based sensing configuration from a server, wherein the receiving device receives the first RF signal, the second RF signal, and the third RF signal according to the FDOA-based sensing configuration.

[0157] Clause 11. The method according to any one of Clauses 8 to 10, the method further comprising: sending the first FDOA and the second FDOA to the server for determining Doppler information of the transmitting device.

[0158] Clause 12. The method according to any one of Clauses 8 to 11, the method further comprising: determining Doppler information of the transmitting device based on the first FDOA and the second FDOA.

[0159] Clause 13. The method according to any one of Clauses 8 to 12, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector with known Doppler information.

[0160] Clause 14. A server for frequency difference of arrival (FDOA)-based sensing of a target, the server comprising a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors are configured to: send an FDOA-based sensing configuration to the transmitting device, wherein the FDOA-based sensing configuration configures the transmitting device to: transmit a first radio frequency (RF) signal at a first time point; transmit a second RF signal at a second time point; and transmit a third RF signal at a third time point. The one or more processors are further configured to: obtain a first FDOA measurement determined based on reflections of the first RF signal and reflections of the second RF signal and a second FDOA measurement determined based on the reflections of the second RF signal and reflections of the third RF signal, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at a receiving device. The one or more processors are further configured to: obtain Doppler information of the reflector; and obtain Doppler information of the transmitting device based on the first FDOA measurement, the second FDOA measurement, and the Doppler information of the reflector.

[0161] Clause 15. The server according to clause 14, wherein the one or more processors are further configured to: determine a location and a velocity of the target based on the Doppler information of the target.

[0162] Clause 16. The server according to any one of clauses 14 or 15, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

[0163] Clause 17. The server according to any one of clauses 14 to 16, wherein the one or more processors are further configured to: receive a request to perform the FDOA-based sensing from the transmitting device, wherein transmitting the FDOA-based sensing configuration is in response to receiving the request.

[0164] Clause 18. The server according to any one of clauses 14 to 17, wherein the one or more processors are further configured to: obtain a frequency offset of the reflection from the receiving device, wherein obtaining the first FDOA measurement and the second FDOA measurement further comprises: determining a frequency difference between the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal and the second FDOA measurement determined from the frequency difference between the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

[0165] Clause 19. The server according to any one of Clauses 14 to 18, wherein the one or more processors are further configured to: determine the Doppler information based on the first FDOA measurement and the second FDOA measurement.

[0166] Clause 20. The server according to any one of Clauses 14 to 19, wherein the reflector comprises a reconfigurable intelligent surface (RIS).

[0167] Clause 21. A device for frequency difference of arrival (FDOA)-based sensing of a target,

[0168] The device comprises a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory. The one or more processors are configured to: receive a reflection of a first radio frequency (RF) signal transmitted by the transmitting device at a first time point; and receive a reflection of a second RF signal transmitted by the transmitting device at a second time point. The one or more processors are further configured to: receive a reflection of a third RF signal transmitted by the transmitting device at a third time point; and determine a frequency offset of the reflections of the first RF signal, the second RF signal, and the third RF signal. The one or more processors are further configured to: determine a first FDOA measurement determined based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal and a second FDOA measurement determined based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

[0169] Clause 22. The device according to Clause 21, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

[0170] Clause 23. The device according to any one of Clauses 21 or 22, wherein the one or more processors are further configured to: receive an FDOA-based sensing configuration from a server, wherein the receiving device receives the first RF signal, the second RF signal, and the third RF signal according to the FDOA-based sensing configuration.

[0171] Clause 24. The device according to any one of Clauses 21 to 23, wherein the one or more processors are further configured to: send the first FDOA and the second FDOA to the server for determining the Doppler information of the transmitting device.

[0172] Clause 25. The apparatus according to any one of Clauses 21 to 24, wherein the one or more processors are further configured to: determine Doppler information of the transmitting device based on the first FDOA and the second FDOA.

[0173] Clause 26. The apparatus according to any one of Clauses 21 to 25, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector having known Doppler information.

Claims

1. A method for server - executed FDOA - based sensing of a transmitting device, the method comprising: Sending an FDOA - based sensing configuration to the transmitting device, wherein the FDOA - based sensing configuration configures the transmitting device to: Transmit a first radio - frequency (RF) signal at a first time point; Transmit a second RF signal at a second time point; And Transmit a third RF signal at a third time point; Obtaining a first FDOA measurement determined based on the reflection of the first RF signal and the reflection of the second RF signal, and a second FDOA measurement determined based on the reflection of the second RF signal and the reflection of the third RF signal, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at a receiving device; Obtaining Doppler information of the reflector; And Obtaining Doppler information of the transmitting device based on the first FDOA measurement, the second FDOA measurement, and the Doppler information of the reflector.

2. The method according to claim 1, the method further comprising: Determining the position and velocity of the transmitting device based on the Doppler information of the transmitting device.

3. The method according to claim 1, wherein the first time point, the second time point, and the third time point are selected from a pre - determined time window.

4. The method according to claim 1, the method further comprising: Receiving a request from the transmitting device to perform the FDOA - based sensing, wherein transmitting the FDOA - based sensing configuration is in response to receiving the request.

5. The method according to claim 1, the method further comprising: Obtaining the frequency offset of the reflection from the receiving device, wherein obtaining the first FDOA measurement and the second FDOA measurement further comprises: Determining the frequency difference between the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal, and the second FDOA measurement determined from the frequency difference between the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

6. The method according to claim 1, wherein obtaining the Doppler information of the transmitting device further comprises: Determining the Doppler information based on the first FDOA measurement and the second FDOA measurement.

7. The method according to claim 1, wherein the reflector comprises a reconfigurable intelligent surface (RIS).

8. A method for receiving - device - executed FDOA - based sensing of a transmitting device, the method comprising: Receiving, at a first time point, the reflection of a first radio - frequency (RF) signal transmitted by the transmitting device; Receiving, at a second time point, the reflection of a second RF signal transmitted by the transmitting device; Receiving, at a third time point, the reflection of a third RF signal transmitted by the transmitting device; Determining the frequency offset of the reflections of the first RF signal, the second RF signal, and the third RF signal; And Determine a first FDOA measurement determined based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal, and a second FDOA measurement determined based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

9. The method according to claim 8, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

10. The method according to claim 8, the method further comprising: Receiving a FDOA-based sensing configuration from a server, wherein the receiving device receives the first RF signal, the second RF signal, and the third RF signal according to the FDOA-based sensing configuration.

11. The method according to claim 10, the method further comprising: Sending the first FDOA and the second FDOA to the server for determining Doppler information of the sending device.

12. The method according to claim 10, the method further comprising: Determining Doppler information of the sending device based on the first FDOA and the second FDOA.

13. The method according to claim 8, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector having known Doppler information.

14. A server for FDOA-based sensing of a sending device, the server comprising: A transceiver; A memory; And One or more processors communicatively coupled to the transceiver and the memory, wherein the one or more processors are configured to: Send a FDOA-based sensing configuration to the sending device, wherein the FDOA-based sensing configuration configures the sending device to: Transmit a first radio frequency (RF) signal at a first time point; Transmit a second RF signal at a second time point; And Transmit a third RF signal at a third time point; Obtain a first FDOA measurement determined based on the reflection of the first RF signal and the reflection of the second RF signal and a second FDOA measurement determined based on the reflection of the second RF signal and the reflection of the third RF signal, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector and received at a receiving device; Obtain the Doppler information of the reflector; And Obtain the Doppler information of the sending device based on the first FDOA measurement, the second FDOA measurement, and the Doppler information of the reflector.

15. The server according to claim 14, wherein the one or more processors are further configured to: Determine the position and velocity of the target based on the Doppler information of the target.

16. The server according to claim 14, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

17. The server according to claim 14, wherein the one or more processors are further configured to: Receive a request to perform the FDOA-based sensing from the sending device, wherein the transmission of the FDOA-based sensing configuration is in response to receiving the request.

18. The server according to claim 14, wherein the one or more processors are further configured to: Obtain the reflected frequency offset from the receiving device, wherein obtaining the first FDOA measurement and the second FDOA measurement further includes: Determining a frequency difference between the reflected frequency offset of the first RF signal and the reflected frequency offset of the second RF signal and the second FDOA measurement determined from the frequency difference between the reflected frequency offset of the second RF signal and the reflected frequency offset of the third RF signal.

19. The server according to claim 14, wherein the one or more processors are further configured to: Determine the Doppler information based on the first FDOA measurement and the second FDOA measurement.

20. The server according to claim 14, wherein the reflector includes a reconfigurable intelligent surface (RIS).

21. A device for FDOA-based sensing for a sending device, the device comprising: A transceiver; A memory; And One or more processors communicatively coupled to the transceiver and the memory, wherein the one or more processors are configured to: Receive a reflection of a first radio frequency (RF) signal transmitted by the sending device at a first time point; Receive a reflection of a second RF signal transmitted by the sending device at a second time point; Receive a reflection of a third RF signal transmitted by the sending device at a third time point; Determine the frequency offsets of the reflections of the first RF signal, the second RF signal, and the third RF signal; And Determine a first FDOA measurement determined based on the frequency offset of the reflection of the first RF signal and the frequency offset of the reflection of the second RF signal and a second FDOA measurement determined based on the frequency offset of the reflection of the second RF signal and the frequency offset of the reflection of the third RF signal.

22. The device according to claim 21, wherein the first time point, the second time point, and the third time point are selected from a pre-determined time window.

23. The device according to claim 21, wherein the one or more processors are further configured to: Receive an FDOA-based sensing configuration from a server, wherein the device receives the first RF signal, the second RF signal, and the third RF signal according to the FDOA-based sensing configuration.

24. The device according to claim 23, wherein the one or more processors are further configured to: Send the first FDOA and the second FDOA to the server for determining the Doppler information of the sending device.

25. The apparatus according to claim 23, wherein the one or more processors are further configured to: Determine Doppler information of the transmitting device based on the first FDOA and the second FDOA.

26. The apparatus according to claim 21, wherein the reflections of the first RF signal, the second RF signal, and the third RF signal are reflected by a reflector having known Doppler information.

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