Dynamic and flexible radio frequency (RF) node pairing for distributed sensing

Abstract

In some implementations, pairing of a first sensing node and a second sensing node for radio frequency (RF) sensing may be performed. To do so, the first sensing node may operate in a Tx detection mode in which the first sensing node: periodically transmits instances of a first reference signal (RS), and periodically attempts to receive instances of a second RS transmitted by the second sensing node. The first sensing node may transition operation from the Tx detection mode to a Tx tracking mode in which the first sensing node: periodically transmits instances of a third RS, in response to detecting a target by the received instances of the second RS transmitted by the second sensing node, and periodically attempting to receive an additional instance of the second RS sent by the second sensing node.

Description

BACKGROUND OF THE DISCLOSURE 1. Technical Field

[0002] The present disclosure generally relates to the field of radio frequency (RF)-based sensing (or simply "RF sensing") in wireless networks such as cellular networks.

[0003] 2. Related Art

[0004] As the complexity of cellular networks such as fourth-generation (4G) and fifth-generation (5G) cellular networks continues to increase, the functionality of such networks extends beyond just data communication. Cellular networks can, for example, provide positioning functionality to determine the geographical location of a cellular mobile device (referred to as "user equipment" (UE)) within the coverage area of the cellular network. Additionally, such networks are expanding into RF sensing in order to be able to detect objects (including their location and velocity) based on the reflection (or echo) of RF signals reflected from the objects. However, the RF signals used for RF sensing are often sent in an inefficient manner, resulting in increased power usage and overhead. SUMMARY OF THE INVENTION

[0005] An example method for pairing a first sensing node and a second sensing node for radio frequency (RF) sensing according to an implementation of the present disclosure may include operating the first sensing node in a Tx detection mode, in which the first sensing node: periodically transmits instances of a first reference signal (RS), and periodically attempts to receive instances of a second RS transmitted by the second sensing node. The method may further include, in response to detecting a target by the received instances of the second RS transmitted by the second sensing node, transitioning the operation of the first sensing node from the Tx detection mode to a Tx tracking mode, in which the first sensing node: periodically transmits instances of a third RS, and periodically attempts to receive additional instances of the second RS transmitted by the second sensing node.

[0006] An example method for pairing a first sensing node and a second sensing node for radio frequency (RF) sensing according to an implementation of the present disclosure may include operating the second sensing node in an Rx detection mode, in which the second sensing node periodically attempts to receive instances of a first reference signal (RS) transmitted by the first sensing node. The method may further include, in response to detecting a target by the received instances of the first RS transmitted by the first sensing node, transitioning the operation of the second sensing node from the Rx detection mode to an Rx tracking mode, in which the second sensing node: periodically transmits instances of a second RS, and periodically attempts to receive instances of a third RS transmitted by the first sensing node.

[0007] An example first sensing node for radio frequency (RF) sensing according to the present disclosure may include: a transceiver; a memory; one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more processors are configured to: operate in a Tx detection mode, in which the first sensing node: periodically transmits an instance of a first reference signal (RS) via the transceiver, and periodically attempts to receive an instance of a second RS transmitted by a second sensing node via the transceiver. The one or more processors may also be configured to transition the operation from the Tx detection mode to a Tx tracking mode in response to detecting a target by the received instance of the second RS transmitted by the second sensing node, in which the first sensing node: periodically transmits an instance of a third RS via the transceiver, and periodically attempts to receive additional instances of the second RS transmitted by the second sensing node via the transceiver.

[0008] An example second sensing node for radio frequency (RF) sensing according to the present disclosure may include: a transceiver; a memory; one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more processors are configured to: operate in an Rx detection mode, in which the second sensing node periodically attempts to receive an instance of a first reference signal (RS) transmitted by the first sensing node. The one or more processors may also be configured to transition the operation from the Rx detection mode to an Rx tracking mode in response to detecting a target by the received instance of the first RS transmitted by the first sensing node, in which the second sensing node: periodically transmits an instance of a second RS, and periodically attempts to receive an instance of a third RS transmitted by the first sensing node.

[0009] This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood with reference to the appropriate portions of the entire specification of this disclosure, any or all of the drawings, and each claim. 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 illustrates a communication / location / sensing system according to one embodiment.

[0011] Figure 2 is a diagram of a distributed sensing system according to one embodiment.

[0012] Figure 3Is a diagram illustrating an example of a process for pairing a transmitting (Tx) node and a receiving (Rx) node according to one embodiment.

[0013] Figure 4 Is illustrative of according to one embodiment Figure 4 The timing diagram of the functionality of the Rx node in the Rx detection mode of.

[0014] Figure 5 Is a timing diagram illustrating the functionality of the Rx node transitioning from the Rx detection mode to the Rx tracking mode according to one embodiment.

[0015] Figure 6 Is illustrative of according to one embodiment the corresponding functionality that the Tx node can implement when the Rx node implements Figure 5 The functionality of.

[0016] Figure 7 Is a timing diagram illustrating the exemplary functionality of the Tx node in the Tx detection mode according to one embodiment.

[0017] Figure 8 Is a timing diagram illustrating the exemplary functionality of the Tx node in a scenario where the Tx node detects an RS transmission from the Rx node but does not detect the target according to one embodiment.

[0018] Figure 9 Is a flowchart of a method for implementing the pairing of a first sensing node and a second sensing node for RF sensing according to one embodiment.

[0019] Figure 10 Is a flowchart of another method for implementing the pairing of a first sensing node and a second sensing node for RF sensing according to one embodiment.

[0020] Figure 11 Is a block diagram of an embodiment of a sensing node.

[0021] Figure 12 Is a block diagram of an embodiment of a computer system.

[0022] Similar reference symbols in the various figures indicate similar elements according to certain example 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 refer to elements 110a, 110b, and 110c). Detailed Implementation Modes

[0023] The following description is directed to certain specific implementations with the aim of describing the innovative aspects of each implementation. However, those of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described specific implementations 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 Wi-Fi ® technologies), Bluetooth ® 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), Evolved 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 with 3G, 4G, 5G, 6G, or further specific implementations thereof).

[0024] As used herein, "RF signal" includes an electromagnetic wave that transmits information through the space between a transmitter (or transmitting device) and a receiver (or receiving device). As used herein, a transmitter can 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 can receive multiple "RF signals" corresponding to each transmitted RF signal.

[0025] Additionally, unless otherwise specified, references to "positioning reference signal", "reference signal for positioning", etc. can be used to refer to signals for positioning a mobile device such as a user equipment (UE) in a 5G New Radio (NR) network. As described in more detail herein, such signals can 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. Additionally, unless otherwise indicated, references to "sensing reference signal", "reference signal for sensing", etc. can be used to refer to signals for RF sensing (also commonly referred to as "sensing" herein) as described herein. Signals for RF sensing and / or positioning can generally be referred to as reference signals (RSs) herein. As described in more detail herein, such signals can include any of a variety of signal types, but may not necessarily be limited to signals used only for RF sensing.

[0026] As previously noted, RF sensing is being envisioned for various applications, including wireless networks such as cellular networks. However, the prior art has envisioned using "always-on" RF signals and / or signals transmitted and received by all RF sensing nodes without regard to the location of the target. This can result in unnecessary overhead, energy / RF resources, inefficient use of sensing nodes, etc. Embodiments herein address these and other user problems by providing a sensing scheme for pairing sensing nodes in a manner that can be implemented in a distributed sensing system, which can provide efficient use of sensing nodes and RF resources and / or other such advantages. Additional details will be provided after a review of the applicable technology.

[0027] Figure 1is a simplified illustration of a wireless system capable of communication, positioning, and sensing according to one embodiment, which wireless system 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 pairing RF sensing nodes. (That is, the embodiment is 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 location of the mobile device 105 based on RF signals received by and / or transmitted from the mobile device 105 and the known locations of other components that send and / or receive RF signals (e.g., GNSS satellites 110, base stations 120, APs 130). Additionally or alternatively, wireless devices such as the mobile device 105, base stations 120, and satellites 110 (and / or other NTN platforms that may be implemented on airplanes, unmanned aerial vehicles, balloons, 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 by using RF signals transmitted by one or more wireless devices).

[0028] It should be noted that Figure 1 only generalized illustrations of the various components are provided, where any or all of the components 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 than Figure 1A greater or lesser number of base stations 120 and / or APs 130 as illustrated. The illustrated connections that couple 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. Additionally, the components may be rearranged, combined, separated, replaced, and / or omitted according to 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.

[0029] 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. Additionally, 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 a Long-Term Evolution (LTE) wireless network, a Fifth Generation (5G) wireless network (also referred to as a New Radio (NR) wireless network or 5G NR wireless network), a 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.

[0030] 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 wireless 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 functionality 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 or all of these functional components. For example, AP 130 may include a Wi-Fi AP or a Bluetooth ® 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, because AP 130 may 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.

[0031] 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 functionality of a TRP may be performed by a transmission point (TP), and / or the reception functionality 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 by 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 beams in different directions (e.g., one after another). 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).

[0032] 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 a 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 transmission and reception point (TRP) (or transmission 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.

[0033] 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 performed by the mobile device 105. According to some embodiments, the location server may include a Home Subscriber Location Platform (H-SLP) for Secure User Plane Location (SUPL), which 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), which 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), which 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.

[0034] 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 sending 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).

[0035] 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, 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 any combination thereof. The wireless signals from the mobile device 145 for locating the mobile device 105 can include using, for example, Bluetooth ® (including Bluetooth Low Energy (BLE)), IEEE 802.11x (e.g., Wi-Fi ®), RF signals of Ultra-Wideband (UWB), IEEE 802.15x, or combinations thereof. The mobile device 145 may additionally or alternatively use non-RF wireless signals for the positioning of the mobile device 105, such as infrared signals or other optical technologies.

[0036] The estimated position 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. "Position" is also referred to herein as "position estimate", "estimated position", "location", "positioning", "positioning estimate", "position fix", "estimated positioning", "location fix", or "fix". The process of determining a position can be referred to as "positioning", "position determination", "location determination", etc. The position of the mobile device 105 can include the absolute position of the mobile device 105 (e.g., latitude and longitude and possibly altitude) or the relative position 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 position (including, for example, the position of the base station 120 or the AP 130) or a certain other position (such as the position of the mobile device 105 at a certain known previous time, or the position of the mobile device 145 (e.g., another UE) at a certain known previous time)). The position can be specified as a geodetic position including coordinates, which can be absolute (e.g., latitude, longitude, and optionally altitude), relative (e.g., relative to a certain known absolute position), 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 position can alternatively be a city position 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 position can also include an indication of uncertainty or error, such as a horizontal distance and possibly a vertical distance for which the position is expected to have an error, 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).

[0037] 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, where the location services can include obtaining and providing the location of the mobile device 105 (e.g., to enable 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.

[0038] As noted, RF devices can enable a system such as the communication / location / sensing system 100 to perform RF sensing. Specifically, multiple RF devices can be distributed over an area or zone to identify objects or "targets" within that area or zone. The type of distributed sensing system can help detect small targets while effectively increasing coverage and avoiding blind spots. Additionally, compared to traditional sensing, distributed sensing can provide spatial flexibility for target detection and tracking.

[0039] Figure 2 is a diagram of a distributed sensing system 200 according to one embodiment. The distributed sensing system 200 can be incorporated into a larger system (e.g., Figure 1 the communication / location / sensing system 100), in which case the components of the distributed sensing system 200 can perform other functions (e.g., related to communication and / or location). In the distributed sensing system 200, sensing nodes (which can be Figure 1 responded to by wireless RF devices, including the mobile device 105, the base station 120, the AP 130, other devices 145, etc.) can be grouped into clusters 210 for providing sensing for a specific area, and multiple clusters ( Figure 2 not shown in the figure) can be used to cover a larger area. The clusters can be controlled by a cluster head 220, which can include a server local to the cluster 210 and / or accessible via the cloud 230. (Thus, in some embodiments, the cluster 220 can correspond to Figure 1 the server 160.) Different clusters can be managed by the same cluster head 220 or different respective cluster heads.

[0040] Generally, the distributed sensing system 200 can use the sensing nodes in the clusters 210 to sense the target 235. These sensing nodes can be paired by the cluster head 220 into transmit (Tx) nodes 240 and receive (Rx) nodes 250 or bistatic and / or multistatic sensing.

[0041] Within the cluster 210, the cluster head 220 can dynamically pair the sensing nodes to effectively detect and track the target 235. In Figure 2In the example, there are six sensing nodes in cluster 210: three Tx nodes 240 and three Rx nodes 250. When target 235 moves through the area covered by cluster 210, cluster head 220 can provide centralized management to activate and deactivate different sensing nodes to detect and track target 235. For example, cluster head 220 can schedule one or more of Tx nodes 240 to send RS and one or more of Rx nodes 250 to detect the time when the sent RS is received (the time when Rx node receives the sent RS can be referred to as RS "estimation" herein), including the reflection of RS from target 235 (thereby detecting target 235). Then, one or more Rx nodes 250 can report the detection status back to cluster head 220. Starting from the initial detection (in some instances, which may involve all sensing nodes), the cluster head can then determine valid node pairs from the sensing nodes for target detection. In Figure 2 In the example, for example, cluster head 220 can analyze the detection results from Rx nodes 250-1, 250-2, and 250-3 regarding the RS sent by Tx nodes 240-1, 240-2, and 240-3 to determine that two sensing node pairs can effectively detect and further track target 235: Tx node 240-3 / Rx node 250-1 and Tx node 240-3 / Rx node 250-3. (Note that Tx node 240-3 is included in both pairs. However, depending on the detection results, any combination of Tx nodes 240 and Rx nodes 250 can be paired or further track target 235.)

[0042] Other embodiments may be different from Figure 2 the described example. For example, in some embodiments, instead of detecting the target by Rx nodes 250, the Rx nodes can simply provide sensing data to cluster head 220, which can then analyze the sensing data to determine the presence of target 235. Additionally, it can be noted that if possible, the sensing nodes can perform beamforming (e.g., as Figure 2 suggested in) to send and / or receive RS in a specific direction. That is, other embodiments may not utilize beamforming. Depending on the desired functionality, additional or alternative variations can be implemented.

[0043] In addition to providing coverage over a potentially large area, distributed sensing can also provide benefits. For example, when compared with single-site sensing, distributed sensing can be more easily implemented. For example, single-site sensing typically requires full-duplex operation, where Tx and Rx are processed simultaneously in one device. Additionally, single-site sensing may require greater power consumption because the RS experiences two-way propagation loss. On the other hand, in distributed sensing, some nodes can be paired to perform bistatic and / or multistatic sensing, where the nodes can be divided into Tx nodes and Rx nodes (e.g., Figure 2As shown in []. In this case, the signal only needs to propagate in one direction (from Tx to Rx), and thus the power consumption can be much smaller than that of single - station sensing for the same coverage. In other words, for power settings and requirements, distributed sensing using Tx nodes and Rx nodes can roughly cover an area twice as large as that covered by a single - station node. Additionally, the Tx nodes and Rx nodes do not need to have full - duplex capabilities. In fact, semi - duplex nodes (e.g., nodes operating as either Tx nodes or Rx nodes) may not be required. Instead, in some configurations, dedicated Tx or Rx nodes can be utilized. This can greatly reduce the amount of complexity (and cost) of the nodes in the distributed sensing system.

[0044] It can be noted that although the above discussion has contrasted single - station sensing in a distributed system with bistatic / multistatic sensing, some implementations of the distributed system may employ single - station sensing (e.g., as a supplement or alternative to bistatic / multistatic sensing).

[0045] Depending on the desired functionality, distributed sensing can also utilize licensed and / or unlicensed RF bands. Compared to unlicensed bands, licensed - band sensing can contribute to the scalability of the sensing setup, given the relative efficiency of using a licensed RF band compared to using an unlicensed band. According to some implementations, in order to enable sensing services (within a licensed band) in an area, sensing nodes can be flexibly enabled or scheduled in a short period of time. This can help ensure that sufficient nodes are scheduled for distributed sensing, including nodes in different clusters.

[0046] As discussed with respect to Figure 2 In distributed sensing, not all nodes in a cluster may contribute to detecting a specific target. Some nodes may provide valuable target information, while other nodes do not provide any information and may provide interference. Thus, in traditional distributed sensing, the activation / de - activation of nodes and the scheduling of RS transmissions / estimations (e.g., by a cluster head) can impose a large resource cost to accurately pair Tx nodes and Rx nodes.

[0047] Traditional distributed sensing methods can be carried out as follows. First, to identify different Tx nodes, each Tx node can be configured with a specific RS, and the Rx node should detect all potential RSs to identify the Tx nodes. In particular, when there are a large number of Tx nodes, the Rx node needs to spend a lot of effort to find the valid RS from a large pre-configured set of RSs. This can be particularly onerous when sensing is multiplexed with communication and sensing resources are limited. Second, the cluster head can collect the estimation results from all Rx nodes, even if only some nodes can detect the sensing signal. Finally, the head finally determines the valid Tx-Rx pairs to detect the target. In these traditional distributed sensing methods, the information (signaling) exchanged between the cluster head and the nodes of the cluster may be relatively large, potentially invading the communication resources. In addition, in some scenarios, the scheduling by the cluster head may not be available, such as when the communication capability is not enabled. In such instances, it may be difficult to determine the valid pairs for sensing.

[0048] The embodiments in this document address these and other problems, thus providing a low-cost over-the-air (OTA) process for pairing Tx nodes and Rx nodes. This process can be widely used in distributed scenarios and can largely avoid the resource costs associated with the communication between the sensing nodes and the cluster head. In addition, the process described in this document can greatly save the RS resources in the Tx and can greatly reduce the estimation burden in the Rx.

[0049] Figure 3 is a diagram illustrating an example of a process for pairing Tx nodes and Rx nodes according to an embodiment. In this example, for the sensing nodes, the following are illustrated: a first Tx 310, a second Tx 320, a first Rx 330, and a second Rx 340. That is, depending on the desired functionality, the cluster can include more or fewer sensing nodes. As Figure 3 shown and described in more detail below, the Tx nodes and Rx nodes can implement detection and tracking modes, where detection is associated with "phase 1" ( Figure 3 boxes 350 and 370) and tracking is associated with "phase 2" (box 360). When in the detection mode or phase 1, the nodes can be considered "unpaired". When in the tracking mode or phase 2, the nodes can be considered "paired".

[0050] In Figure 3 the example, all nodes start unpaired (at phase 1, box 350), and the second Tx 320 and the first Rx 330 become paired for a certain period of time (at phase 2, box 360), and then return to the unpaired state (phase 1, at box 370). As described in more detail below with respect to the subsequent figures, when implementing different modes, the Tx nodes and Rx nodes can implement different functionalities or "cycles" to provideFigure 3 The functionality illustrated in. Each mode may involve sending or receiving an instance of a particular RS. In the embodiments herein, different RRs are generally referred to as RS-1, RS-2, and RS-3 and are described in more detail below. In Figure 3 The modes and signal types are illustrated in boxes labeled 380 and 390, respectively, in.

[0051] As illustrated, all nodes start in the detection mode, and the first Tx 310 and the second Rx 340 remain unpaired. For the second Rx 340, it remains in the Rx detection mode, in which it monitors instances of RS-1. Since the second Rx 340 (i) does not receive RS-1 or (ii) receives an RS-1 in which no target is detected, it remains unpaired (in the Rx detection mode) without changing the mode. Similarly, for the first Tx 310, it remains in the Tx detection mode, in which it periodically sends RS-1 while also monitoring instances of RS-2. Since the first Tx 310 (i) does not receive RS-2, and / or (ii) receives an RS-2 in which no target is detected, it remains unpaired (in the Tx detection mode) without changing the mode.

[0052] The process proceeds differently for the second Tx 320 and the first Rx 330, which travel through stage 1 (box 350) to stage 2 (box 360), and then back to stage 1 (box 370), as previously noted. In stage 1 (the "unpaired" stage), the second Tx 320 and the first Rx 330 are in the same detection mode as the first Tx 310 and the second Rx 340. That is, RS-1 is sent by the Tx nodes according to a predefined sparse resource pattern. According to some embodiments, all Tx nodes may send the same RS (e.g., RS-1), and all Rx nodes may be configured to detect that RS. Based on predefined rules, the Rx nodes may determine whether a target is detected in any of the received RRs.

[0053] When the first Rx 330 detects a target via the RS-1 transmitted by the second Tx 320, the second Tx 320 and the first Rx 330 transition to Phase 2 (block 360). After receiving the RS-1 in which the target is detected, the first Rx 330 can then transition to a detection mode, in which it monitors RS-3 while transmitting RS-2. If the second Tx 320 detects a target via the RS-2 transmitted by the first Rx 330, it can then transition to a tracking mode, in which it transmits RS-3 and continues to monitor RS-2 simultaneously. When the second Tx 320 and Rx 330 are in these tracking modes, these nodes can be considered paired, and the process proceeds as indicated in Phase 2 (block 360). In the tracking mode, the second Tx 320 can transmit RS-3 more frequently than it transmitted RS-1 in Phase 1, in order to accurately sense the detected target. In some embodiments, the transmission of RS-3 can be considered "dense", and the transmission of RS-1 can be considered "sparse". The second Tx 320 can remain in the tracking mode and continue to transmit RS-3 until the target is no longer detected.

[0054] According to some embodiments, when the first Rx 330 no longer detects a target, it can stop transmitting RS-2 and resume back to Phase 1, in which the first Rx 330 is no longer paired and operates in an Rx detection mode in which it monitors RS-1. When the second Tx 320 determines that the first Rx 330 has stopped transmitting RS-2 (e.g., the second Tx 320 has determined that a scheduled or expected RS-2 has not been transmitted), it can also resume back to a Tx detection mode (Phase 1, as shown by block 370), thereby transmitting RS-1 while monitoring RS-2.

[0055] Channel reciprocity can help ensure that the relevant Tx node and Rx node are properly paired. That is, due to channel reciprocity, the target detected by the first Rx 330 from RS-1 should also be detected by the second Tx 320 from RS-2 (and subsequently detected by the first Rx 330 from RS-3). Other nodes will not detect the target unless the target also affects the RF channel between the Tx and Rx nodes. Therefore, Figure 3 the process has built-in efficiency in pairing only the relevant nodes of detectable targets. In addition, the nodes can automatically transition to different modes without being scheduled or configured to do so by a central device such as a cluster head or a management server. Therefore, Figure 3 the process in can reduce overhead by reducing the traffic between the sensing nodes and the central device.

[0056] Figures 4 to 8 is a diagram illustrating the functionality that can be performed by a Tx node and an Rx node when in different modes. The execution of this functionality can result inFigure 3 Pairing of nodes in the manner exemplified by the process.

[0057] Figure 4 Is exemplified Figure 3 A timing diagram of the functionality of the Rx node in the Rx detection mode, where the Rx node monitors RS-1 when not paired. Here, the functionality is exemplified as a pair of loops, including an RS transmission loop 400 and an RS estimation loop 410. The RS transmission loop 400 exemplifies the RS transmission performed by the Rx node. In this case, since no target is detected, no RS transmission is performed. The RS estimation of 410 exemplifies a time window 420, where the Rx node attempts to receive the RS transmission sent from one or more Tx nodes and determines whether a target is detected. The periodicity of the time window 420 can be predetermined (e.g., by a management device, such as a cluster head), and can correspond to the transmissions made by one or more Tx nodes in the same cluster as the Rx node. Again, since no target has been detected yet, the periodicity can represent a predefined sparse pattern to help conserve RF resources. Additionally, since no RS is received and since no target is detected, the Rx node can continue to repeat Figure 4 The functionality exemplified in.

[0058] Figure 5 Is a timing diagram of the functionality of the Rx node that transitions from the Rx detection mode to the Rx tracking mode (e.g., during the second phase) after detecting a target. Here, the RS transmission loop 500 and the RS estimation loop 510 can initially Figure 4 Proceed in the manner exemplified in. Specifically, the Rx node initially operates in the Rx detection mode where the Rx node may not transmit RS, but instead may listen for the RS transmissions made by one or more Tx nodes during the time window 520. In this example, the RS transmission is not received at the first time window 520-1, but is received later at the second time window 520-2. The reception of the RS transmission (e.g., Figure 3 Of RS-1) from one or more Tx nodes within the estimation window 520 and the detection of the target are represented by the target detection box 530 within the time window 520. (To avoid clutter, many target detection boxes 530 and time windows 520 are not labeled in Figure 5 ). After detecting the target, the Rx node can then enter the Rx tracking mode, where the Rx node makes a periodic RS transmission 540 (e.g., Figure 3 Of RS-2) to indicate to the Tx node that a target has been detected, and adjusts the estimation window 520 to detect additional RS transmissions from the Tx node during the time period 550 where the Rx node is paired with the Tx node (e.g., Figure 3RS-3). The timing and frequency of the RS transmissions from the Tx node during time period 550 (e.g., dense detection mode) can be predefined such that the estimated time window 520 of the Rx node matches the transmission time of the Tx node. Time period 550 can correspond to Figure 3 phase 2.

[0059] The time period 550 during which the Rx node and the Tx node are paired can end when the Rx node no longer detects the target. In Figure 5 the example, the Rx node may not detect the target (or the RS transmission) in the third time window 520-3, in which case the Rx node stops the periodic RS transmission 540, which signals to the Tx that the target is no longer detected. Then, the Tx node stops the dense RS transmissions performed during time period 550 and resumes back to the Tx detection mode, where the Tx node performs sparse transmissions for target detection. Additionally or alternatively, if the Tx node does not detect the periodic RS transmission 540 of the Rx node, and / or does not detect the target on the periodic RS transmission 540, then the Tx node can stop the dense RS transmissions and resume back to the Tx detection mode. This can signal to the Rx node that the target is no longer detected and that the Tx node is no longer in the tracking mode. When resuming back to the detection mode, the Rx node and the Tx node may no longer be considered paired (but can be paired again if the target is subsequently detected).

[0060] Figure 6 is a timing diagram illustrating the corresponding functionality that the Tx node can implement when the Rx node implements Figure 5 the functionality. Similar to Figure 4 and Figure 5 ,, Figure 6 includes an RS estimation loop 600 and an RS transmission loop 610. (Note that, contrary to Figure 4 and Figure 5 the loop 610 for estimating Figure 6 is at the top of the figure, and the transmission loop 610 is at the bottom of the figure.) As shown in the RS estimation loop 600, the Tx node can periodically monitor the RS transmissions sent from the Rx node during the time window 620 (e.g., it can occur again according to a predefined transmission schedule). Specifically, the Tx node can operate in the Tx detection mode, where it transmits an RS transmission 630 (e.g., RS-1) during the time window 620 and monitors the RS transmissions from one or more Rx nodes (e.g., RS-2), which corresponds to Figure 3 the functionality of the second Tx 320 in phase 1. The target detection box 640 represents the instances where the Tx node (i) receives an RS transmission from the Rx node and (ii) detects the target from the received transmission. ( Figure 6The first instance of the box 640 in [description] may correspond to an RS transmission made by an Rx node that detected a target in the first RS transmission 630 of the Tx node. ) As previously indicated, after receiving an RS transmission from an Rx node and detecting a target from the received transmission, the Tx node may then enter the Tx tracking mode (e.g., corresponding to phase 2 or pairing mode) or a time period 650 during which the Tx node may make relatively dense RS transmissions to track the detected target. The node will remain in the target detection mode until the target is no longer detected. As previously indicated, if the Rx node no longer detects the target, it may stop RS transmissions. Otherwise, the Tx node may not detect the target from the Rx transmission. In either case, if the target is no longer detected during the time window 620-2, in which case the Tx node may resume back to phase 1, in which it may transmit a sparse RS transmission pattern.

[0061] Figure 7 is a timing diagram illustrating the example functionality of a Tx node in the Tx detection mode. Again, the functionality is illustrated as a pair of loops, including an RS estimation loop 700 and an RS transmission loop 710. Here, the RS estimation loop 700 includes a periodic time window 720 during which the Tx node attempts to detect an RS transmission from the Rx node. Again, the timing and periodicity of the time window 720 may be predefined (e.g., by a management device, such as a cluster head) and may correspond to transmissions made by one or more Rx nodes in the same cluster as the Tx node. Additionally, the Tx node transmits a series of RS transmissions 730 or target detections made by one or more Rx nodes. However, since [description] Figure 7 no target was detected in the example, no change to the functionality is made. Again, the periodicity of the RS transmissions 730 while in Tx detection may represent a predefined sparse pattern to help conserve RF resources.

[0062] Figure 8 is a timing diagram illustrating the example functionality of a Tx node in a scenario where the Tx node detects an RS transmission (e.g., RS-2) from an Rx node but does not detect a target. In [description] Figure 8 the example, an RS estimation 800 loop is shown, and two options are shown for the RS transmission loop: a first RS transmission loop 810 corresponding to a first option and a second RS transmission loop 815 corresponding to a second option. Although there may be channel reciprocity, the Tx node may not detect the target (detected by the Rx node) if the RS transmission (e.g., RS-2) transmitted by the Rx node does not match a predefined condition (such as a threshold SNR).

[0063] According to the first option, in the manner described in the above-discussed embodiments with respect to the Tx detection mode, the Tx node may transmit the RS transmission 820 and perform an estimation during the time window 830. However, if the Tx node receives an RS transmission from the Rx node during one or more time windows, as shown in the time window 840, the Tx node may stop transmitting the RS transmission 820. As shown in the first RS transmission cycle 810, the time 850 is the time when the Tx node would transmit the periodic RS transmission 820 but does not transmit. Instead, the Tx node suppresses the transmission of the RS transmission 820 until a target (not shown) is detected during the estimation window or no RS transmission is received. If no RS transmission is received from the Rx node during the estimation window, as shown at the estimation window 830-2, the Tx node may resume transmission, as indicated by the RS transmission 820-2. By suppressing the RS transmission in this manner, the Tx node may help save power and avoid potential RF interference from other paired nodes. Alternatively, as illustrated by the second RS transmission cycle 815, the Tx node may simply continue to transmit the RS transmission 820.

[0064] As described in the embodiments herein, different RSs may be used for different purposes. Generally, different RSs (e.g., RS-1, RS-2, RS-3) may differ in timing / repetition, waveform, frequency, and / or other aspects that enable the receiving node to distinguish between different RSs. (As mentioned herein, an individual transmission of an RS may be referred to as an RS "transmission" or "instance.") Utilizing different RSs for different purposes (e.g., as described herein with respect to RS-1, RS-2, and RS-3) may enable the receiving node to determine the mode (e.g., tracking or detection) in which the transmitting node is operating. According to some embodiments, all Tx nodes and Rx nodes utilize the same RS or the same functionality. For example, all Tx nodes in a cluster may transmit RS-1 for sensing in the detection mode, all Rx nodes in the cluster may transmit RS-2 for sensing in the tracking mode, and all Tx nodes in the cluster may transmit RS-3 for sensing in the tracking mode. It may be noted that in a distributed sensing setup, most nodes typically operate within the detection mode most of the time. Sharing a common RS for all nodes may help reduce overhead (e.g., in signal processing).

[0065] Additionally or alternatively, embodiments may utilize a specific RS (e.g., RS-2) to indicate the so-read target information from the Rx node to the Tx node, and the transmission of such RS (e.g., RS-2) may be much sparser than the RS (e.g., RS-1) used in the detection mode. Further, the RS transmitted by the Rx node during the tracking mode may not be specifically designed for accuracy (whereas the RS transmitted by the Tx node during the tracking mode may be designed for accuracy). Thus, the implementation of the RS (e.g., RS-2) transmitted by the Rx node during tracking may be relaxed. For example, it may not be necessary to maintain the phase continuity between adjacent RS signals transmitted by the Rx node during tracking.

[0066] According to some embodiments, the RS (e.g., RS-3) transmitted by the Tx node for sensing in the tracking mode may have a denser pattern (e.g., higher repetition rate) and / or wider bandwidth than other RS signals (e.g., RS-1 and RS-2). In some instances, the RS (e.g., RS-3) transmitted by the Tx node for sensing in the tracking mode may include the same RS as the RS (e.g., RS-1) transmitted by the Tx node for sensing in the detection mode, but with a denser transmission pattern. By reusing the RS, it may avoid interference to detection in unpaired Rx nodes, where the compromise is that it may increase the likelihood of interference to paired nodes. Additionally or alternatively, the RS (e.g., RS-3) transmitted by the Tx node in the tracking mode may be a specific RS for sensing in the tracking mode. By using a specific RS in this manner, paired nodes may avoid potential interference from other unpaired nodes.

[0067] According to some embodiments, the RS (e.g., RS-1) transmitted by the Tx node during detection and the RS (e.g., RS-2) transmitted by the Rx node during tracking may include the same RS, or may be selected from one predefined common RS pool. For example, if all Tx nodes (e.g., in a cluster) reuse the same RS-1, the Rx node may receive multiple RS-1s from different Tx nodes. Although this may increase the likelihood of interference, the cost of reusing RS-1 is low because the search space is small (the pool size is only 1). In contrast, by using a predefined RS pool, each node may randomly pick an RS with different seeds / periodicity. Although such a pool may reduce the interference level, it increases the search cost. Considering these trade-offs, it may be desirable to reuse the same RS-1 in a sparse distributed setting where the likelihood of interference is low.

[0068] Regarding the use of a common RS pool, two types of RS pools can be considered. One type is an RS pool with a small size, which is used for sparse distributed sensing scenarios. This can help reduce the search cost and can be used in sparse distributed sensing scenarios where the interference likelihood is low (e.g., at any given time, only a limited number of nodes within the RF sensing range can be scheduled for sensing). In our school, the other type of RS pool has a relatively large size that can be used for dense distributed sensing (e.g., at any given time, a relatively large number of nodes within the RF sensing range can be scheduled for sensing). Using a larger pool in dense distributed sensing scenarios can help reduce the interference likelihood. However, as noted above, this increases the search space and thus increases the processing cost.

[0069] As noted, the use of a common RS may make it unclear to the receiving node which node sent the RS. For example, a Tx / Rx node may not know which node it is paired with and may be paired with multiple nodes. For example, in the previously described embodiments, all Tx nodes that can detect RS-2 are paired, and all Rx nodes that can detect RS-3 are paired. Additionally, as also described herein, nodes must remain paired until the target is out of coverage (or otherwise no longer detected). Although a node may not know the identity of one or more nodes it is paired with, a centralized device (e.g., Figure 2 cluster head 220) can still be used to determine sensing. That is, each node can report sensing data to a server, which can use the reported data and known information about the nodes (e.g., the respective locations of each node, scheduled transmit times, etc.) to determine information about the detected target (e.g., the location of the target, Doppler, etc.).

[0070] Depending on the desired functionality, the sensing data obtained by the sensing nodes and provided to the server for target detection can vary. According to some embodiments, the sensing data can include range, SNR, and / or Doppler information for each of one or more detected targets. The sensing data can be used to determine information about the target, such as location, shape, speed, or a combination thereof. According to some embodiments, predefined sensing rules can be configured to enable one or more services, such as identifying targets of interest. For example, for pedestrian detection, certain rules regarding speed can be used to filter out vehicles. When there is a target with a speed of 70 km / h, it can be assumed that it is not a pedestrian and can be ignored. Thus, rules can be defined to identify the desired targets within the received signals. Additionally, sensing settings (e.g., RS periodicity, range, etc.) can be established to ensure that proper sensing is performed to achieve any predefined sensing rules. According to some embodiments, based on predefined rules provided by the server to the Rx nodes, the Rx nodes can determine whether there are targets of interest.

[0071] As discussed with respect to Figures 3 to 8 both the Tx and Rx sensing nodes can send and receive the RSs for sensing. For example, in the Tx detection mode, the Tx node sends RS-1 and monitors RS-2. Additionally, in the Rx detection mode, the Rx node monitors RS-3 and sends RS-2. In this way, each node can be half-duplex (e.g., perform time division duplex (TDD)), or can be full-duplex (able to send and receive simultaneously). However, in some distributed sensing setups, low-layer (e.g., low-cost) nodes can be utilized, where the nodes have either a transmit or a receive capability, but not both. In such embodiments, a hybrid approach can be used, where the low-layer nodes with only a transmit or a receive capability can be paired with other nodes having complementary functionality. For example, an Rx node with only a detection capability, an adjacent high-layer (e.g., half-duplex or full-duplex) Rx node can be used to assist in RS-2 transmission during the Rx tracking mode. Similarly, for a Tx node with only a transmit capability, an adjacent high-layer Tx node can assist in RS-2 reception.

[0072] In such embodiments, the high-layer nodes can be reused to provide additional sensing capabilities. As an example, if a first Tx node (e.g., a low-layer node) has only a transmit capability, and a second Tx node nearby (e.g., a high-layer node) has both a transmit and a receive capability, the second Tx node can assist the first Tx node in RS-2 reception. In this example, the two nodes can be connected by a wired connection (e.g., to facilitate communication between the two nodes without using wireless resources). Similar implementations can be made using Rx nodes.

[0073] Furthermore, according to some embodiments, if one low-layer node has only a transmit capability and another low-layer node has only a receive capability, they can be used as a single high-layer node with both a transmit and a receive capability (e.g., an Rx node or a Tx). This utilization can be done as needed. For example, if a receive-only Rx node in the detection mode needs to transition to the tracking mode (where it needs to send RS-2), a nearby transmit-only node can be configured (e.g., on the fly when the transition occurs) to send RS-2.

[0074] According to some embodiments, once the Tx node and the Rx node have been paired, additional signaling can be performed. For example, the paired Tx node and Rx node can report sensing data including the estimated results of the received RS-2 and RS-3 to a server (e.g., a cluster head). By reporting the information simultaneously, the paired nodes can help reduce the likelihood of false alarms (e.g., false detection of a target). Additionally, this type of coordinated reporting can also be used to jointly determine the location of the target.

[0075] Depending on the desired functionality, the content and format of the sensed data reported to the server may vary. For example, according to some embodiments, the report of the sensed data by the sensing node may include an indication of whether the sensing node is paired (e.g., a single-bit indication), information about the detected target (e.g., range, signal strength of the target, Doppler information, or a combination thereof). This information, together with the joint report of the paired nodes, can further help reduce false alarms and determine the location of the target. For example, if the estimated signal strength is very low and only one or two nodes in a relatively dense cluster detect the target, the cluster head may consider the detection of the target as a false alarm. Additionally, with as few as two nodes, using an indication of the beam used for sensing (e.g., angle information in addition to range information), the localization of the target is possible.

[0076] Figure 9 is a flowchart of a method 900 for implementing the pairing of a first sensing node and a second sensing node for RF sensing according to one embodiment. Figure 9 The functionality illustrated in the box of can be performed, for example, by a Tx node as described herein. For performing Figure 9 The structure / components for performing the functionality illustrated in one or more of the boxes shown can be performed by the hardware and / or software components of the sensing node. Figure 11 Example components of the sensing node are illustrated in and are described in more detail below.

[0077] At block 910, the functionality includes operating the first sensing node in a Tx detection mode, in which the first sensing node: periodically transmits an instance of a first RS, and periodically attempts to receive an instance of a second RS transmitted by the second sensing node. As Figure 7 illustrated, for example, a Tx node can periodically transmit (RS transmission cycle 710) and periodically attempt to receive (RS estimation cycle 700) RS to detect an object. According to some embodiments, the first sensing node can periodically transmit an instance of the first RS at a higher repetition rate in a Tx tracking mode compared to the repetition rate at which the first sensing node periodically attempts to receive an instance of the second RS transmitted by the second sensing node. Additionally or alternatively, the first RS and the second RS can be selected from a common RS pool.

[0078] The structure / components for performing the functionality at block 910 can include a bus 1105, a processor 1110, a digital signal processor (DSP) 1120, a wireless communication interface 1130, a sensing unit 1150, a memory 1160, or other components of the sensing node 1100, or any combination thereof. In Figure 11 such components are illustrated and described below.

[0079] At block 920, the functionality includes transitioning the operation of the first sensing node from the Tx detection mode to the Tx tracking mode in response to detecting a target in response to an instance of the second RS received from the second sensing node, in which the first sensing node in the Tx tracking mode: periodically transmits an instance of a third RS, and periodically attempts to receive additional instances of the second RS transmitted by the second sensing node. As relative to Figure 6 As illustrated, the transmission of the third RS may be more frequent than the transmission of the first and / or second RS. Thus, according to some embodiments of method 900, the first sensing node may transmit the instance of the third RS at a higher repetition rate in the Tx tracking mode as compared to the repetition rate at which the first sensing node periodically transmits the instance of the first RS in the Tx detection mode.

[0080] The structure / components for performing the functionality at block 920 may include bus 1105, processor 1110, digital signal processor (DSP) 1120, wireless communication interface 1130, sensing unit 1150, memory 1160, or other components of sensing node 1100, or any combination thereof. Such components are illustrated in Figure 11 and described hereinafter.

[0081] As described in the previously described embodiments, depending on the desired functionality, embodiments may include additional features. For example, the RS transmission may be predefined (e.g., obtained from a predefined or pre-established resource pool). Thus, according to some embodiments, the periodic transmission of the instance of the first RS, the periodic attempt to receive the instance of the second RS, the periodic transmission of the instance of the third RS, or any combination thereof may be according to a configuration received by the first sensing node from a server.

[0082] Furthermore, as noted, the sensing node may transition back to the detection mode from the tracking mode when the object is no longer detected. For example, some embodiments of method 900 may further include transitioning the operation of the first sensing node back from the Tx tracking mode to the Tx detection mode, where transitioning the operation of the first sensing node back to the Tx detection mode is in response to: the first sensing node not detecting the target by an additional instance of the second RS received from the second sensing node, or the first sensing node not receiving an additional instance of the second RS transmitted by the second sensing node. Or, in some embodiments, the first sensing node does not detect the target by the received second RS. That is, as relative to Figure 8As described, if the target is not detected in one or more instances of the second RS, the implementation may respond differently. For example, according to some implementations, in response to receiving a particular instance of the second RS sent by the second sensing node and not detecting the target through the particular instance of the second RS, the first sensing node pauses the periodic transmission of the instance of the first RS when operating in the Tx detection mode. That is, according to some implementations, the first sensing node may simply continue to perform the periodic transmission of the instances of the first RS.

[0083] The implementation may also include performing sensing. For example, some implementations include obtaining sensing data from the received instances of the second RS sent by the second sensing node and transmitting the sensing data from the first sensing node to the server. In such implementations, the sensing data may also include information indicating: the range between the target and the first sensing node, the signal-to-noise ratio (SNR) of the received instances of the second RS sent by the second sensing node, Doppler information about the target, or any combination thereof.

[0084] Figure 10 FIG. 1000 is a flowchart of another method for implementing the pairing of a first sensing node and a second sensing node for RF sensing according to one implementation. Figure 10 The functions illustrated in the block of FIG. 1000 may be performed, for example, by an Rx node as described herein. The structures / components for performing the functions illustrated in one or more of the blocks of FIG. 1000 may be performed by the hardware and / or software components of the sensing node. Figure 10 FIG. 1100 illustrates example components of a sensing node, which are described in more detail below. Figure 11 FIG. 1100 illustrates example components of a sensing node, which are described in more detail below.

[0085] At block 1010, the function includes operating the second sensing node in an Rx detection mode, in which the second sensing node periodically attempts to receive an instance of the first RS sent by the first sensing node. As previously discussed, an example of the Rx detection mode is illustrated in FIG. 1000. The structures / components for performing the function at block 1010 may include a bus 1105, a processor 1110, a digital signal processor (DSP) 1120, a wireless communication interface 1130, a sensing unit 1150, a memory 1160, or other components of the sensing node 1100, or any combination thereof. Such components are illustrated in FIG. 1100 and described below. Figure 4 FIG. 1100 illustrates example components of a sensing node, which are described in more detail below. Figure 11 Such components are illustrated in FIG. 1100 and described below.

[0086] At block 1020, the functionality includes transitioning the operation of the second sensing node from an Rx detection mode to an Rx tracking mode in response to detecting a target in an instance of a first RS received from a first sensing node, where in the Rx tracking mode the second sensing node: periodically transmits an instance of a second RS, and periodically attempts to receive an instance of a third RS transmitted by the first sensing node. In Figure 5 an example of the transition from the Rx detection mode to the Rx tracking mode is provided. The structure / components for performing the functionality at block 1020 may include a bus 1105, a processor 1110, a digital signal processor (DSP) 1120, a wireless communication interface 1130, a sensing unit 1150, a memory 1160, or other components of the sensing node 1100, or any combination thereof. In Figure 11 such components are illustrated and described hereinafter.

[0087] As described in the previously described embodiments, depending on the desired functionality, embodiments may include additional features. For example, the periodic attempt to receive an instance of the first RS transmitted by the first sensing node, the periodic transmission of an instance of the third RS, the periodic attempt to receive an instance of the third RS transmitted by the first sensing node, or any combination thereof may be according to a configuration received by the second sensing node from a server. In some embodiments, method 1000 may further include transitioning the operation of the second sensing node back to the Rx detection mode, where transitioning the operation of the first sensing node back to the Rx detection mode is in response to: the second sensing node not detecting a target in an instance of the third RS received from the first sensing node, or the second sensing node not receiving an instance of the third RS transmitted by the first sensing node.

[0088] As explained elsewhere herein, the repetition rates of the various RSs may reflect the desired functionality. According to some embodiments, the second sensing node may attempt to receive the instance of the third RS transmitted by the first sensing node at a higher repetition rate compared to the repetition rate at which the second sensing node periodically attempts to receive the instance of the first RS transmitted by the first sensing node. Additionally or alternatively, the second sensing node may attempt to receive the instance of the first RS transmitted by the first sensing node at a higher repetition rate compared to the repetition rate at which the first sensing node periodically transmits the instance of the second RS. According to some embodiments, the first RS and the second RS are selected from a common RS pool.

[0089] Similarly, data may be transmitted to a server for performing and / or processing sensing. According to some embodiments, method 1000 may further include obtaining sensing data from an instance of the third RS received from the first sensing node and transmitting the sensing data from the second sensing node to the server. In such embodiments, the sensing data may further include information indicating: the range between the target and the second sensing node, the signal-to-noise ratio (SNR) of the instance of the third RS received from the first sensing node, Doppler information about the target, or any combination thereof.

[0090] Figure 11 FIG. is a block diagram of an embodiment of a sensing node 1100 that may be used to perform RF sensing as described herein (e.g., in connection with the foregoing figures). In some embodiments, for example, sensing node 1100 may include, for example, a mobile (e.g., movable / portable) device (e.g., a UE, a tablet, a laptop, a vehicle, etc.). In some embodiments, sensing node 1100 may include a fixed (e.g., immovable) electronic device. It should be noted that Figure 11 only intends to provide a generalization of the various components, any or all of which may be utilized as the case may be. Additionally, the functionality of the sensing nodes discussed herein may be performed by Figure 11 one or more of the hardware and / or software components illustrated.

[0091] Sensing node 1100 is shown as including hardware elements that may be electrically coupled (or otherwise communicatively coupled as the case may be) via a bus 1105. The hardware elements may include a processor 1110, which may include, but is not limited to, one or more general-purpose processors (e.g., application processors), one or more dedicated processors (such as a digital signal processor (DSP) chip, a graphics acceleration processor, an application specific integrated circuit (ASIC), etc.), and / or other processing structures or components. Processor 1110 may include one or more processing units, which may be housed in a single integrated circuit (IC) or multiple ICs. As Figure 11 shown, depending on the desired functionality, some embodiments may have a separate DSP 1120. Wireless communication-based position determination and / or other determinations (discussed below) may be provided in processor 1110 and / or wireless communication interface 1130. Sensing node 1100 may also include one or more input devices 1170, which may include, but are not limited to, one or more keyboards, touchscreens, touch pads, microphones, buttons, dials, switches, etc.; and one or more output devices 1115, which may include, but are not limited to, one or more displays (e.g., touchscreens), light emitting diodes (LEDs), speakers, etc.

[0092] The sensing node 1100 may further include a wireless communication interface 1130, which may 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 Bluetooth ® devices, IEEE 802.11 devices, IEEE 802.15.4 devices, Wi-Fi devices, WiMAX devices, WAN devices, and / or various cellular devices, etc.), which may enable the sensing node 1100 to communicate with other devices as described in the above embodiments. The wireless communication interface 1130 may permit communicating (e.g., sending and receiving) data and signaling with a base station of a network (e.g., via an eNB, gNB, ng-eNB, access point, various base stations, and / or other access node types, and / or other network components), a computer system, and / or any other electronic device communicatively coupled to the base station as described herein. Communication may be performed via one or more wireless communication antennas 1132 that transmit and / or receive wireless signals 1134. According to some embodiments, the wireless communication antennas 1132 may include multiple discrete antennas, an antenna array, or any combination thereof. The antenna 1132 may be capable of transmitting and receiving wireless signals using beams (e.g., Tx beams and Rx beams). Beamforming may be performed using digital and / or analog beamforming techniques with corresponding digital and / or analog circuits. The wireless communication interface 1130 may include such circuits.

[0093] According to the desired functionality, the wireless communication interface 1130 may include a separate receiver and transmitter, or a transceiver, any combination of a transmitter and / or a receiver, to communicate with base stations (e.g., ng-eNB and gNB) and other terrestrial transceivers (such as wireless devices and access points). The sensing node 1100 may communicate with different data networks, which may include various network types. For example, one such network type may include a wireless wide area network (WWAN), which may be a code division multiple access (CDMA) network, a time division multiple access (TDMA) network, a frequency division multiple access (FDMA) network, an orthogonal frequency division multiple access (OFDMA) network, a single carrier frequency division multiple access (SC-FDMA) network, a WiMAX (IEEE 802.16) network, and so on. A CDMA network may implement one or more radio access technologies (RATs), such as CDMA2000 ® 、wideband code division multiple access (WCDMA), etc. CDMA2000 ®including IS-95, IS-2000, and / or IS-856 standards. The TDMA network can implement Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), or some other RAT. The OFDMA network can employ Long-Term Evolution (LTE), LTE-Advanced, Fifth Generation (5G) New Radio (NR), and so on. 5G NR, LTE, LTE-Advanced, GSM, and WCDMA are described in documents from the Third Generation Partnership Project (3GPP). CDMA2000 ® is described in documents from an organization named "Third Generation Partnership Project 2" (3GPP2). 3GPP and 3GPP2 documents are publicly available. The wireless local area network (WLAN) can also be an IEEE802.11x network, and the wireless personal area network (WPAN) can be a Bluetooth network, IEEE 802.15x, or some other type of network. The techniques described herein can also be used for any combination of WWAN, WLAN, and / or WPAN.

[0094] The sensing node 1100 may also include a sensor 1140. The sensor 1140 may include, but is not limited to, one or more inertial sensors and / or other sensors (e.g., accelerometers, gyroscopes, cameras, magnetometers, altimeters, microphones, proximity sensors, light sensors, barometers, etc.), some of which sensing can be used to obtain location-related measurements and / or other information.

[0095] Embodiments of the sensing node 1100 may also include a sensing unit 1150. The sensing unit 1150 may include hardware and / or software components capable of transmitting and / or receiving RF signals (e.g., RS) to detect one or more targets in the manner described herein. The sensing unit 1150 may include separate components connected to the bus 1105, as illustrated, or may be incorporated into another component (e.g., the wireless indication interface 1130). Additionally, the sensing unit 1150 may be communicatively coupled to the antenna 1132, and the sensing unit may share the antenna with the wireless communication interface 1130. Additionally or alternatively, the sensing unit 1150 may have its own antenna (not shown). In some embodiments, the sensing unit 1150 may be communicatively coupled to multiple antennas or antenna arrays capable of transmitting and / or receiving RF signals via a directional beam.

[0096] An implementation of the sensing node 1100 may also include a Global Navigation Satellite System (GNSS) receiver 1180 that is capable of receiving signals 1184 from one or more GNSS satellites using an antenna 1182 (which may be the same as antenna 1132). The positioning measured based on the GNSS signals may be used to supplement and / or incorporate the techniques described herein. The GNSS receiver 1180 may use conventional techniques to extract the positioning of the sensing node 1100 from GNSS satellites of GNSS systems such as the Global Positioning System (GPS), Galileo, GLONASS, the Quasi-Zenith Satellite System (QZSS) covering Japan, the Indian Regional Navigation Satellite System (IRNSS), the BeiDou Navigation Satellite System (BDS) covering China, etc. Additionally, the GNSS receiver 1180 may be used in conjunction with various augmentation systems (e.g., satellite-based augmentation systems (SBAS)) that may be associated with or otherwise enabled to work with one or more global and / or regional navigation satellite systems, such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multi-functional Satellite Augmentation System (MSAS), and the GPS Aided Geo Augmented Navigation (GAGAN) system, etc.

[0097] It may be noted that although the GNSS receiver 1180 is illustrated as a different component in Figure 11 the implementation is not limited thereto. As used herein, the term "GNSS receiver" may include hardware and / or software components configured to obtain GNSS measurements (measurements from GNSS satellites). Thus, in some implementations, the GNSS receiver may include (as software) a measurement engine executed by one or more processors such as processor 1110, DSP 1120, and / or a processor within the wireless communication interface 1130 (e.g., in a modem). The GNSS receiver may also optionally include a positioning engine that may use the GNSS measurements from the measurement engine to determine the positioning of the GNSS receiver using an Extended Kalman Filter (EKF), Weighted Least Squares (WLS), particle filters, etc. The positioning engine may also be executed by one or more processors such as processor 1110 or DSP 1120.

[0098] The sensing node 1100 may also include a memory 1160 and / or communicate with the memory. The memory 1160 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 random access memory (RAM) and / or read only memory (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.

[0099] The memory 1160 of the sensing node 1100 may also include software elements ( Figure 11 not shown), which include 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 executable by the sensing node 1100 (and / or the processor 1110 or DSP 1120 within the sensing node 1100) in the memory 1160. 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.

[0100] Figure 12 is a block diagram of an embodiment of a computer system 1200, which may be used, in whole or in part, to provide the functionality of one or more components and / or devices as described in embodiments herein, including a server (e.g., a sensing server / SMF and / or a cluster head) that communicates with one or more sensing nodes to coordinate RF sensing as described in embodiments herein. This may include, for example, computer servers, personal computers, personal electronic devices, etc. It should be noted that Figure 12 it is only intended to provide a generalization of the various components, any or all of which may be utilized as appropriate. Thus, Figure 12 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 12 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.

[0101] Computer system 1200 is shown as including hardware elements that may be electrically coupled (or otherwise communicatively coupled as appropriate) via bus 1205. The hardware elements may include a processor 1210, 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, which may be configured to execute one or more of the methods described herein. Computer system 1200 may also include one or more input devices 1215, which may include, but are not limited to, a mouse, a keyboard, a camera, a microphone, etc.; and one or more output devices 1220, which may include, but are not limited to, a display device, a printer, etc.

[0102] Computer system 1200 may also include one or more non-transitory storage devices 1225 (and / or communicatively coupled 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 random access memory (“RAM”) and / or read-only memory (“ROM”)), which may be programmable, 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 a hub, as described herein.

[0103] Computer system 1200 may also include a communication subsystem 1230, which may include wireless communication technologies managed and controlled by a wireless communication interface 1233, as well as wired technologies (such as Ethernet, coaxial communication, universal serial bus (USB), etc.). The wireless communication interface 1233 may include one or more wireless transceivers, which may transmit and receive wireless signals 1255 (e.g., signals according to 5G NR or LTE) via a wireless antenna 1250. Thus, the communication subsystem 1230 may include a modem, a network card (wireless or wired), an infrared communication device, a wireless communication device, and / or a chipset, etc., which may enable computer system 1200 to communicate with any device on any or all of the communication networks described herein (including user equipment (UE), base stations, and / or other transmit / receive points (TRP), and / or any other electronic device described herein) on the corresponding network. Therefore, the communication subsystem 1230 may be used to receive and transmit data, as described in the embodiments herein.

[0104] In many embodiments, computer system 1200 will also include a working memory 1235, which may include RAM or ROM devices as described above. Software elements shown as being located within working memory 1235 may include an operating system 1240, device drivers, executable libraries, and / or other code (such as one or more applications 1245), 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 procedures 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 in accordance with the described methods.

[0105] This set of instructions and / or code may be stored on a non-transitory computer-readable storage medium (such as the storage device 1225 described above). In some cases, the storage medium may be incorporated within a computer system such as computer system 1200. In other embodiments, the storage medium may be separate from the computer system (e.g., a removable medium such as an optical disc), and / or may be provided in an installation package so that the storage medium can be used to program, configure, and / or adapt a general purpose computer on which the instructions / code are stored. These instructions may take the form of executable code executable by computer system 1200 and / or may take the form of source code and / or installable code, which, when compiled and / or installed on computer system 1200 (e.g., using any of a variety of commonly available compilers, installers, compression / decompression utilities, etc.), takes the form of executable code.

[0106] It will be apparent to those skilled in the art that basic variations may be made in accordance with specific requirements. For example, customized hardware may also be used, and / or specific elements may be implemented in hardware, software (including portable software such as applets, etc.), or both. Additionally, connections to other computing devices such as network input / output devices may be employed.

[0107] Referring to the accompanying drawings, components that may include a memory may include a non-transitory machine-readable medium. 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.

[0108] The methods, systems, and devices discussed herein are examples. Various embodiments may omit, substitute, or add various procedures 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 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 and do not limit the scope of the disclosure to those specific examples.

[0109] It has proven convenient, primarily for common reasons, to sometimes refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, numerical symbols, 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," "associating," "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, transmission devices, or display devices of the special-purpose computer or similar special-purpose electronic computing device.

[0110] 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 an inclusive sense) as well as A, B, or C (here used in an exclusive sense). In addition, as used herein, the term "one or more" may be used to describe any feature, structure, or characteristic in a singular form or may be used to describe some combination of features, structures, or characteristics. It should be noted, however, that this is merely illustrative 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, may be interpreted to mean any combination of A, B, and / or C, such as A, AB, AA, AAB, AABBCCC, etc.

[0111] Several embodiments have been described and various modifications, alternative constructions, and equivalent forms may 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, a number of steps may be performed before, during, or after consideration of the above elements. Accordingly, the above description does not limit the scope of the disclosure.

[0112] In view of this description, various embodiments may include different combinations of features. Specific examples of embodiments are described in the following numbered clauses:

[0113] Clause 1. A method of implementing pairing of a first sensing node and a second sensing node for radio frequency (RF) sensing, the method comprising: operating the first sensing node in a Tx detection mode in which the first sensing node: periodically transmits instances of a first reference signal (RS), and periodically attempts to receive instances of a second RS transmitted by the second sensing node; and in response to detecting a target by an instance of the second RS received from the second sensing node, transitioning the operation of the first sensing node from the Tx detection mode to a Tx tracking mode in which the first sensing node: periodically transmits instances of a third RS, and periodically attempts to receive additional instances of the second RS transmitted by the second sensing node.

[0114] Clause 2. The method according to Clause 1, wherein the periodic transmission of the instances of the first RS, the periodic attempt to receive the instances of the second RS, the periodic transmission of the instances of the third RS, or any combination thereof is according to a configuration received by the first sensing node from a server.

[0115] Clause 3. The method according to any one of Clauses 1 to 2, the method further comprising transitioning the operation of the first sensing node from the Tx tracking mode back to the Tx detection mode, wherein transitioning the operation of the first sensing node back to the Tx detection mode is in response to: the first sensing node not detecting the target via an additional instance of the second RS transmitted by the second sensing node, or the first sensing node not receiving an additional instance of the second RS transmitted by the second sensing node.

[0116] Clause 4. The method according to any one of Clauses 1 to 3, wherein the first sensing node periodically transmits the instances of the third RS at a higher repetition rate in the Tx tracking mode compared to the repetition rate at which the first sensing node periodically transmits the instances of the first RS in the Tx detection mode.

[0117] Clause 5. The method according to any one of Clauses 1 to 4, wherein in response to receiving a specific instance of the second RS transmitted by the second sensing node and not detecting the target via the specific instance of the second RS, the first sensing node pauses the periodic transmission of the instances of the first RS while operating in the Tx detection mode.

[0118] Clause 6. The method according to any one of Clauses 1 to 5, wherein the first sensing node periodically transmits the instances of the first RS at a higher repetition rate in the Tx tracking mode compared to the repetition rate at which the first sensing node periodically attempts to receive the instances of the second RS transmitted by the second sensing node.

[0119] Clause 7. The method according to any one of Clauses 1 to 6, wherein the first RS and the second RS are selected from a common RS pool.

[0120] Clause 8. The method according to any one of Clauses 1 to 7, the method further comprising: obtaining sensing data from an instance of the second RS transmitted by the second sensing node; and transmitting the sensing data from the first sensing node to a server.

[0121] Clause 9. The method according to Clause 8, wherein the sensing data further comprises information indicating: the range between the target and the first sensing node, the signal-to-noise ratio (SNR) of the instance of the second RS received from the second sensing node, Doppler information about the target, or any combination thereof.

[0122] Clause 10. A method for implementing pairing of a first sensing node and a second sensing node for radio frequency (RF) sensing, the method comprising: operating the second sensing node in an Rx detection mode, in which the second sensing node periodically attempts to receive an instance of a first reference signal (RS) transmitted by the first sensing node; and in response to detecting a target by the received instance of the first RS transmitted by the first sensing node, transitioning the operation of the second sensing node from the Rx detection mode to an Rx tracking mode, in which the second sensing node: periodically transmits an instance of a second RS, and periodically attempts to receive an instance of a third RS transmitted by the first sensing node.

[0123] Clause 11. The method according to clause 10, wherein the periodic attempt to receive the instance of the first RS transmitted by the first sensing node, the periodic transmission of the instance of the third RS, the periodic attempt to receive the instance of the third RS transmitted by the first sensing node, or any combination thereof is according to a configuration received by the second sensing node from a server.

[0124] Clause 12. The method according to any one of clauses 10 to 11, the method further comprising transitioning the operation of the second sensing node back to the Rx detection mode, wherein transitioning the operation of the first sensing node back to the Rx detection mode is in response to: the second sensing node not detecting the target by the received instance of the third RS transmitted by the first sensing node, or the second sensing node not receiving the instance of the third RS transmitted by the first sensing node.

[0125] Clause 13. The method according to any one of clauses 10 to 12, wherein the second sensing node periodically attempts to receive the instance of the third RS transmitted by the first sensing node at a higher repetition rate than the repetition rate at which the second sensing node periodically attempts to receive the instance of the first RS transmitted by the first sensing node.

[0126] Clause 14. The method according to any one of clauses 10 to 13, wherein the second sensing node periodically attempts to receive the instance of the first RS transmitted by the first sensing node at a higher repetition rate than the repetition rate at which the first sensing node periodically transmits the instance of the second RS.

[0127] Clause 15. The method according to any one of clauses 10 to 14, wherein the first RS and the second RS are selected from a common RS pool.

[0128] Clause 16. The method according to any one of Clauses 10 to 15, the method further comprising: obtaining sensing data from an instance of the third RS transmitted by the first sensing node received; and transmitting the sensing data from the second sensing node to a server.

[0129] Clause 17. The method according to Clause 16, wherein the sensing data further comprises information indicating: a range between the target and the second sensing node, a signal-to-noise ratio (SNR) of the instance of the third RS transmitted by the first sensing node received, Doppler information about the target, or any combination thereof.

[0130] Clause 18. A first sensing node for radio frequency (RF) sensing, the first sensing node 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: operate in a Tx detection mode, in which the first sensing node: periodically transmits an instance of a first reference signal (RS) via the transceiver, and periodically attempts to receive an instance of a second RS transmitted by a second sensing node via the transceiver; and in response to detecting a target by the instance of the second RS transmitted by the second sensing node received, transition the operation from the Tx detection mode to a Tx tracking mode, in which the first sensing node: periodically transmits an instance of a third RS via the transceiver, and periodically attempts to receive an additional instance of the second RS transmitted by the second sensing node via the transceiver.

[0131] Clause 19. The first sensing node according to Clause 18, wherein the one or more processors are configured to periodically transmit the instance of the first RS, periodically attempt to receive the instance of the second RS, periodically transmit the instance of the third RS, or any combination thereof according to a configuration received by the first sensing node from a server.

[0132] Clause 20. The first sensing node according to any one of Clauses 18 to 19, wherein the one or more processors are configured to transition back from the Tx tracking mode to the Tx detection mode in response to: not detecting the target by the additional instance of the second RS transmitted by the second sensing node received, or not receiving the additional instance of the second RS transmitted by the second sensing node.

[0133] Clause 21. The first sensing node according to any one of Clauses 18 to 20, wherein the one or more processors are configured to periodically transmit the instances of the third RS at a higher repetition rate in the Tx tracking mode than the repetition rate of the instances of the first RS that the one or more processors are configured to periodically transmit in the Tx detection mode.

[0134] Clause 22. The first sensing node according to any one of Clauses 18 to 21, wherein the one or more processors are configured to pause the periodic transmission of the instances of the first RS when operating in the Tx detection mode in response to receiving a specific instance of the second RS transmitted by the second sensing node and not detecting the target through the specific instance of the second RS.

[0135] Clause 23. The first sensing node according to any one of Clauses 18 to 22, wherein the one or more processors are configured to periodically transmit the instances of the first RS at a higher repetition rate in the Tx tracking mode than the repetition rate at which the one or more processors are configured to periodically attempt to receive the instances of the second RS transmitted by the second sensing node.

[0136] Clause 24. The first sensing node according to any one of Clauses 18 to 23, wherein the first RS and the second RS are selected from a common RS pool.

[0137] Clause 25. The first sensing node according to any one of Clauses 18 to 24, wherein the one or more processors are further configured to: obtain sensing data from the received instances of the second RS transmitted by the second sensing node; and transmit the sensing data from the first sensing node to a server.

[0138] Clause 26. A second sensing node for radio frequency (RF) sensing, the second sensing node 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: operate in an Rx detection mode in which the second sensing node periodically attempts to receive instances of a first reference signal (RS) transmitted by the first sensing node; and in response to detecting a target through the received instances of the first RS transmitted by the first sensing node, transition the operation from the Rx detection mode to an Rx tracking mode in which the second sensing node: periodically transmits instances of a second RS, and periodically attempts to receive instances of a third RS transmitted by the first sensing node.

[0139] Clause 27. The second sensing node according to Clause 26, wherein the one or more processors are configured to periodically attempt to receive the instance of the first RS transmitted by the first sensing node, periodically transmit the instance of the third RS, periodically attempt to receive the instance of the third RS transmitted by the first sensing node, or any combination thereof, according to the configuration received by the second sensing node from the server.

[0140] Clause 28. The second sensing node according to any one of Clauses 26 to 27, wherein the one or more processors are further configured to transition the operation from the Rx tracking mode back to the Rx detection mode in response to: the target not being detected by the received instance of the third RS transmitted by the first sensing node, or the instance of the third RS transmitted by the first sensing node not being received.

[0141] Clause 29. The second sensing node according to any one of Clauses 26 to 28, wherein the one or more processors are configured to periodically attempt to receive the instance of the third RS transmitted by the first sensing node at a higher repetition rate compared to the repetition rate at which the one or more processors are configured to periodically attempt to receive the instance of the first RS transmitted by the first sensing node.

[0142] Clause 30. The second sensing node according to any one of Clauses 26 to 29, wherein the one or more processors are configured to periodically attempt to receive the instance of the first RS transmitted by the first sensing node at a higher repetition rate compared to the repetition rate at which the one or more processors are configured to periodically transmit the instance of the second RS.

[0143] Clause 31. An apparatus having components for performing the method according to any one of Clauses 1 to 17.

[0144] Clause 32. A non-transitory computer-readable medium storing instructions, the instructions including code for performing the method according to any one of Clauses 1 to 17.

Claims

1. A method for pairing a first sensing node and a second sensing node for radio frequency (RF) sensing, the method comprises: operating the first sensing node in a Tx detection mode, in which the first sensing node: periodically transmits instances of a first reference signal (RS), and periodically attempts to receive instances of a second RS transmitted by the second sensing node; and in response to detecting a target by an instance of the second RS received from the second sensing node, transitioning the operation of the first sensing node from the Tx detection mode to a Tx tracking mode, in which the first sensing node: periodically transmits instances of a third RS, and periodically attempts to receive additional instances of the second RS transmitted by the second sensing node.

2. The method according to claim 1, wherein the periodic transmission of the instances of the first RS, the periodic attempt to receive the instances of the second RS, the periodic transmission of the instances of the third RS, or any combination thereof is according to a configuration received by the first sensing node from a server.

3. The method according to claim 1, the method further comprising transitioning the operation of the first sensing node back to the Tx detection mode, wherein transitioning the operation of the first sensing node back to the Tx detection mode is in response to: the first sensing node not detecting the target by an additional instance of the second RS received from the second sensing node, or the first sensing node not receiving an additional instance of the second RS transmitted by the second sensing node.

4. The method according to claim 1, wherein the first sensing node periodically transmits the instances of the third RS at a higher repetition rate in the Tx tracking mode compared to the repetition rate at which the first sensing node periodically transmits the instances of the first RS in the Tx detection mode.

5. The method according to claim 1, wherein in response to receiving a specific instance of the second RS transmitted by the second sensing node and not detecting the target by the specific instance of the second RS, the first sensing node pauses the periodic transmission of the instances of the first RS while operating in the Tx detection mode.

6. The method according to claim 1, wherein the first sensing node periodically transmits the instances of the first RS at a higher repetition rate in the Tx tracking mode compared to the repetition rate at which the first sensing node periodically attempts to receive the instances of the second RS.

7. The method according to claim 1, wherein the first RS and the second RS are selected from a common RS pool.

8. The method according to claim 1, the method further comprises: obtaining sensing data from an instance of the second RS received from the second sensing node; and transmitting the sensing data from the first sensing node to a server.

9. The method according to claim 8, wherein the sensed data further includes information indicating: the range between the target and the first sensing node, the signal-to-noise ratio (SNR) of an instance of the second RS received from the second sensing node, Doppler information about the target, or any combination thereof.

10. A method for implementing pairing of a first sensing node and a second sensing node for radio frequency (RF) sensing, the method comprising: operating the second sensing node in an Rx detection mode, in which the second sensing node periodically attempts to receive an instance of a first reference signal (RS) transmitted by the first sensing node; and in response to detecting a target by receiving the instance of the first RS transmitted by the first sensing node, transitioning the operation of the second sensing node from the Rx detection mode to an Rx tracking mode, in which the second sensing node: periodically transmits an instance of a second RS, and periodically attempts to receive an instance of a third RS transmitted by the first sensing node.

11. The method according to claim 10, wherein the periodic attempt to receive the instance of the first RS transmitted by the first sensing node, the periodic transmission of the instance of the third RS, the periodic attempt to receive the instance of the third RS transmitted by the first sensing node, or any combination thereof is according to a configuration received by the second sensing node from a server.

12. The method according to claim 10, the method further comprising transitioning the operation of the second sensing node back to the Rx detection mode, wherein transitioning the operation of the first sensing node back to the Rx detection mode is in response to: the second sensing node not detecting the target by receiving the instance of the third RS transmitted by the first sensing node, or the second sensing node not receiving the instance of the third RS transmitted by the first sensing node.

13. The method according to claim 10, wherein the second sensing node periodically attempts to receive the instance of the third RS transmitted by the first sensing node at a higher repetition rate than the repetition rate at which the second sensing node periodically attempts to receive the instance of the first RS transmitted by the first sensing node.

14. The method according to claim 10, wherein the second sensing node periodically attempts to receive the instance of the first RS transmitted by the first sensing node at a higher repetition rate than the repetition rate at which the first sensing node periodically transmits the instance of the second RS.

15. The method according to claim 10, wherein the first RS and the second RS are selected from a common RS pool.

16. The method according to claim 10, the method further comprising: obtaining sensed data from the instance of the third RS received from the first sensing node; and Transmit the sensed data from the second sensing node to the server.

17. The method according to claim 16, wherein the sensed data further includes information indicating: the range between the target and the second sensing node, the signal-to-noise ratio (SNR) of an instance of the third RS received and transmitted by the first sensing node, Doppler information about the target, or any combination thereof.

18. A first sensing node for radio frequency (RF) sensing, the first sensing node 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: operate in a Tx detection mode, in which the first sensing node: periodically transmits an instance of a first reference signal (RS) via the transceiver, and periodically attempts to receive an instance of a second RS transmitted by a second sensing node via the transceiver; and in response to detecting a target by an instance of the second RS received and transmitted by the second sensing node, transition the operation from the Tx detection mode to a Tx tracking mode, in which the first sensing node: periodically transmits an instance of a third RS via the transceiver, and periodically attempts to receive additional instances of the second RS transmitted by the second sensing node via the transceiver.

19. The first sensing node according to claim 18, wherein the one or more processors are configured to periodically transmit the instance of the first RS, periodically attempt to receive the instance of the second RS, periodically transmit the instance of the third RS, or any combination thereof, according to a configuration received by the first sensing node from a server.

20. The first sensing node according to claim 18, wherein the one or more processors are configured to transition back from the Tx tracking mode to the Tx detection mode in response to: not detecting the target by an additional instance of the second RS received and transmitted by the second sensing node, or not receiving an additional instance of the second RS transmitted by the second sensing node.

21. The first sensing node according to claim 18, wherein the one or more processors are configured to periodically transmit the instance of the third RS at a higher repetition rate in the Tx tracking mode than the repetition rate at which the one or more processors are configured to periodically transmit the instance of the first RS in the Tx detection mode.

22. The first sensing node according to claim 18, wherein the one or more processors are configured to pause the periodic transmission of the instance of the first RS when operating in the Tx detection mode in response to receiving a particular instance of the second RS transmitted by the second sensing node and not detecting the target by the particular instance of the second RS.

23. The first sensing node according to claim 18, wherein the one or more processors are configured to periodically transmit an instance of the first RS at a higher repetition rate in the Tx tracking mode as compared to a repetition rate at which the one or more processors are configured to periodically attempt to receive the instance of the second RS transmitted by the second sensing node.

24. The first sensing node according to claim 18, wherein the first RS and the second RS are selected from a common RS pool.

25. The first sensing node according to claim 18, wherein the one or more processors are further configured to: obtain sensing data from an instance of the second RS received from the second sensing node; and transmit the sensing data from the first sensing node to a server.

26. A second sensing node for radio frequency (RF) sensing, the second sensing node 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: operate in an Rx detection mode in which the second sensing node periodically attempts to receive an instance of a first reference signal (RS) transmitted by the first sensing node; and in response to detecting a target by an instance of the first RS received from the first sensing node, transition the operation from the Rx detection mode to an Rx tracking mode, in which the second sensing node: periodically transmits an instance of a second RS, and periodically attempts to receive an instance of a third RS transmitted by the first sensing node.

27. The second sensing node according to claim 26, wherein the one or more processors are configured to periodically attempt to receive the instance of the first RS transmitted by the first sensing node, periodically transmit the instance of the third RS, periodically attempt to receive the instance of the third RS transmitted by the first sensing node, or any combination thereof, according to a configuration received by the second sensing node from a server.

28. The second sensing node according to claim 26, wherein the one or more processors are further configured to transition the operation back to the Rx detection mode in response to: not detecting the target by an instance of the third RS received from the first sensing node, or not receiving the instance of the third RS transmitted by the first sensing node.

29. The second sensing node according to claim 26, wherein the one or more processors are configured to periodically attempt to receive the instance of the third RS transmitted by the first sensing node at a higher repetition rate as compared to a repetition rate at which the one or more processors are configured to periodically attempt to receive the instance of the first RS transmitted by the first sensing node.

30. The second sensing node according to claim 26, wherein the one or more processors are configured to periodically attempt to receive the instance of the first RS transmitted by the first sensing node at a higher repetition rate than the repetition rate at which the one or more processors are configured to periodically transmit the instance of the second RS.

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