Radio frequency sensing using a single device based on concurrent transmission and reception

Abstract

Techniques are provided for radio frequency (RF) sensing using a single wireless device. An example method for determining a distance to an object with RF sensing includes transmitting, on a wireless device, an RF signal with a transmit channel, receiving, on the wireless device, a leakage signal with a receive channel at a first time, such that the leakage signal is based on the RF signal, receiving, on the wireless device, a reflection signal with the receive channel at a second time, such that the reflection signal is based on the RF signal reflected from the object, and determining the distance to the object based at least in part on a difference between the first time and the second time.

Description

[0001] Cross-references to related applications

[0002] This patent application claims priority to U.S. Patent Application No. 17 / 242,589, filed April 28, 2021, entitled “RADIO FREQUENCY SENSING USINGA SINGLE DEVICE BASED ON CONCURRENT TRANSMIT AND RECEIVE,” which has been assigned to the assignee of this application and whose entire contents are expressly incorporated herein by reference. Background Technology

[0003] A Wireless Local Area Network (WLAN) can be formed by one or more access points (APs) that provide a shared wireless medium for use by multiple client devices. Each AP, corresponding to a Basic Service Set (BSS), can periodically broadcast beacon frames to enable compatible client devices within the AP's wireless range to establish and maintain communication links with the WLAN. WLANs operating according to the IEEE 802.11 series of standards are commonly referred to as Wi-Fi networks, and client devices communicating with APs in Wi-Fi networks can be called radio stations (STAs).

[0004] Some wireless devices can be configured to communicate with other wireless devices using radio-frequency signals. For example, a network may include several Internet of Things (IoT) objects and devices configured to communicate wirelessly with each other. Many IoT devices, such as smart appliances, smart TVs, and smart thermostats, can be configured to support wireless protocols such as Wi-Fi and / or Bluetooth. The wireless channel between the wireless device and the access point (AP) can be used for radio-frequency (RF) sensing applications. Devices can listen to and capture channel parameters transmitted between devices. Objects can be detected based on changes in the channel state between wireless devices. Summary of the Invention

[0005] An example method for determining the distance to an object using radio frequency sensing according to this disclosure includes: transmitting a radio frequency signal on a wireless device using a transmission channel; receiving a leaked signal on the wireless device using a reception channel at a first time, such that the leaked signal is based on the radio frequency signal; receiving a reflected signal on the wireless device using a reception channel at a second time, such that the reflected signal is based on the radio frequency signal reflected from the object; and determining the distance to the object based at least in part on the difference between the first time and the second time.

[0006] Implementation of this method may include one or more of the following features: The radio frequency (RF) signal may be a pre-defined sequence. The pre-defined sequence may be a single-carrier Zadoff-Chu sequence. The pre-defined sequence may include orthogonal frequency division multiplexing (OFDM) symbols. The pre-defined sequence may include one or more Wi-Fi packets. Multiple RF signals can be transmitted and one or more of the multiple RF signals can be received. The method may include transmitting multiple RF signals using multiple transmit channels. Receiving RF signals may include receiving RF signals using multiple receive links. The angle of arrival and angle of departure of the received and transmitted RF signals can be determined. Transmitting and receiving RF signals may be performed using single-link transmit and receive operations.

[0007] An example apparatus according to this disclosure includes: a memory; at least one transceiver including at least one transmit chain and at least one receive chain; at least one processor communicatively coupled to the memory and at least one transceiver, and configured to transmit a radio frequency signal using at least one transmit chain, receive a leaked signal using at least one receive chain at a first time such that the leaked signal is based on the radio frequency signal, receive a reflected signal using at least one receive chain at a second time such that the reflected signal is based on the radio frequency signal reflected from an object, and determine the distance to the object based at least in part on the difference between the first time and the second time.

[0008] Implementation of such a device may include one or more of the following features: The radio frequency (RF) signal may be a pre-defined sequence. The pre-defined sequence may be a single-carrier Zadoff-Chu sequence, may include orthogonal frequency division multiplexing (OFDM) symbols, and / or may include one or more Wi-Fi packets. The at least one processor may be further configured to transmit multiple RF signals and receive one or more of the multiple RF signals. The at least one processor may be further configured to transmit multiple RF signals using multiple transmit chains. The at least one processor may be further configured to receive RF signals using multiple receive chains. The at least one processor may be further configured to determine the angle of arrival of the received RF signal. The at least one processor may be further configured to determine the angle of departure of the RF signal. The at least one processor may be configured to transmit and receive RF signals using single-chain transmit and receive operations.

[0009] An example apparatus for determining the distance to an object using radio frequency sensing according to this disclosure includes: components for transmitting a radio frequency signal on a wireless device using a transmission channel; components for receiving a leaked signal on a wireless device using a reception channel at a first time, such that the leaked signal is based on the radio frequency signal; components for receiving a reflected signal on a wireless device using a reception channel at a second time, such that the reflected signal is based on the radio frequency signal reflected from the object; and components for determining the distance to the object based at least in part on the difference between the first time and the second time.

[0010] A non-transitory processor-readable storage medium includes processor-readable instructions to cause one or more processors to determine a distance to an object using radio frequency sensing according to the present invention. The non-transitory processor-readable storage medium includes: code for transmitting a radio frequency signal on a wireless device using a transmit channel; code for receiving a leaked signal on a wireless device using a receive channel at a first time, such that the leaked signal is based on the radio frequency signal; code for receiving a reflected signal on a wireless device using a receive channel at a second time, such that the reflected signal is based on the radio frequency signal reflected from the object; and code for determining the distance to the object based at least in part on the difference between the first time and the second time.

[0011] An example method for determining the distance to an object using radio frequency sensing according to this disclosure includes: setting the receiving gain on a wireless device to a first level; transmitting a radio frequency signal using the wireless device at a first time such that the wireless device receives a leaked signal at the first level of receiving gain; setting the receiving gain on the wireless device to a second level; receiving a reflection of the radio frequency signal using the wireless device at a second time such that the receiving gain is at the second level; and determining the distance to the object based at least in part on the difference between the first time and the second time.

[0012] An example apparatus according to this disclosure includes: a memory; at least one transceiver; at least one processor communicatively coupled to the memory and the at least one transceiver, and configured to set a receive gain on a wireless device to a first level, transmit a radio frequency signal using the wireless device at a first time such that the wireless device receives a leaked signal at the first level of receive gain, set a receive gain on the wireless device to a second level, receive a reflection of the radio frequency signal using the wireless device at a second time such that the receive gain is at the second level, and determine the distance to an object based at least in part on the difference between the first time and the second time.

[0013] An example method for setting a transmit gain for radio frequency sensing according to this disclosure includes: setting a first transmit gain to avoid receiver saturation; transmitting a first signal using the first transmit gain; receiving a reflection of the first signal and estimating a transmit gain adjustment value; transmitting a second signal using the transmit gain adjustment value; and receiving a reflection of the second signal and estimating a transmit gain adjustment value.

[0014] An example method for controlling a receiver for radio frequency sensing in a wireless device according to the present disclosure includes: setting a receiving gain on the wireless device to a first level; transmitting a radio frequency signal using the wireless device at a first time, wherein the wireless device receives a leaked signal with a receiving gain at the first level; setting a receiving gain on the wireless device to a second level; receiving a reflection of the radio frequency signal using the wireless device at a second time, wherein the receiving gain is at the second level; and determining the distance to an object based at least in part on the difference between the first time and the second time.

[0015] The items and / or techniques described herein may provide one or more of the following capabilities, as well as others not mentioned. Wireless devices are configured to transmit radio frequency (RF) sensing signals. After transmitting the RF sensing signal, the gain of one or more receiver chains in the wireless device may be increased. The RF sensing signal may be reflected by an object and detected by the receiver chain. The distance and orientation to the object can be determined. A single wireless device may be used for indoor mapping. The RF sensing signal may be a WiFi signal. The bandwidth of the RF sensing signal may vary. User posture can be detected. Other capabilities may be provided, and not every implementation according to this disclosure is required to provide any, let alone all, of the capabilities discussed. Attached Figure Description

[0016] Figure 1 This is a block diagram of an example wide area network (WLAN).

[0017] Figure 2 This is a block diagram of the components of an example wireless device.

[0018] Figure 3 This is a block diagram of the components of the example access point.

[0019] Figure 4 This is a conceptual diagram of radio frequency sensing, where wireless devices perform concurrent transmission and reception.

[0020] Figure 5 yes Figure 4 A diagram illustrating example received signals in a wireless device.

[0021] Figure 6 This is a conceptual diagram of in-chain transmission and reception for wireless devices.

[0022] Figure 7 This is an exemplary flowchart of a method for setting the transmit gain for radio frequency sensing.

[0023] Figure 8 This is an exemplary flowchart of a method for setting the receiver gain for radio frequency sensing.

[0024] Figure 9This is an exemplary flowchart of a method for controlling a receiver for radio frequency sensing in a wireless device.

[0025] Figure 10 This is an exemplary flowchart of a method for determining the distance to an object using radio frequency sensing. Detailed Implementation

[0026] This article discusses techniques for RF sensing using a single wireless device. Channel acquisition techniques and RF sensing have become important features in many wireless networks. For example, several Wi-Fi access points compliant with IEEE 802.11ac and 802.11ax support channel acquisition-based RF sensing, which could enable RF sensing applications. However, these existing solutions have limitations and are not suitable for many applications. Typically, existing channel acquisition techniques require a readily accessible second wireless device to transmit a wireless signal (e.g., Wi-Fi packets) so that the first wireless device can listen for the signal and acquire the channel. The need for two wireless devices eliminates the use of RF sensing in situations where only a single wireless device is available, or where there is no wireless traffic to listen for and acquire the channel (e.g., in a car, or at night when device traffic is low). In addition, the second wireless device may have some kind of transmission behavior that causes changes in channel acquisition even when there is no movement, such as transmit chain switching, random phase between transmit chains, etc., which may degrade RF sensing performance. Using two devices also presents challenges in determining the accurate location of movement (i.e., determining whether the movement is near the first or second device).

[0027] The techniques presented herein provide an RF sensing system using only a single wireless device. This single wireless system can be configured to determine channel capture using concurrent transmission and reception without requiring another wireless device or additional wireless traffic. This technique reduces or eliminates the interoperability issues faced by previous two-device current channel capture methods because it uses a single wireless device. Furthermore, using a single wireless system eliminates the ambiguity of location identification. The single wireless device described herein can be used for mapping applications, sensing user presence, detecting user gestures, and other RF sensing applications. These techniques and configurations are examples, and other techniques and configurations can be used.

[0028] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the scope of this disclosure. Various processes or components may be appropriately omitted, substituted, or added to the various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Similarly, features described with reference to some examples may be combined in other examples.

[0029] First refer to Figure 1 The block diagram illustrates an example of a WLAN network 100, such as a network implementing at least one of the IEEE 802.11 family of standards. The WLAN network 100 may include an access point (AP) 105 and one or more wireless devices 110 or stations (STAs), such as mobile stations, personal digital assistants (PDAs), other handheld devices, netbooks, laptops, tablets, laptops, display devices (e.g., televisions, computer monitors, etc.), printers, IoT devices, etc. Although only one AP 105 is shown, the WLAN network 100 may have multiple APs 105. Each wireless device 110, also referred to as a mobile station (MS), mobile device, access terminal (AT), user equipment (UE), subscriber station (SS), or subscriber unit, may be associated with and communicate with the AP 105 via a communication link 115. Each AP 105 has a geographical coverage area 125, such that wireless devices 110 within this area can generally communicate with the AP 105. The wireless devices 110 may be distributed throughout the geographical coverage area 125. Each wireless device 110 may be stationary or mobile. For illustrative purposes, the principles of this disclosure are described in the context of wireless systems. However, it will be understood that these principles are not necessarily limited to wireless systems and can also be implemented in devices and systems configured for communication via wired connections.

[0030] Wireless device 110 can be covered by more than one AP 105 and therefore can be associated with one or more APs 105 at different times. A single AP 105 and its associated set of stations can be referred to as a Basic Service Set (BSS). An Extended Service Set (ESS) is a set of connected BSSs. A Distributed System (DS) is used to connect APs 105 in the Extended Service Set. The geographical coverage area 125 of access point 105 can be divided into sectors that constitute only a part of the coverage area. WLAN network 100 can include different types of access points 105 (e.g., metropolitan area network, home network, etc.) with different sizes of coverage areas and overlapping coverage areas for different technologies. In other examples, other wireless devices can communicate with AP 105.

[0031] Although wireless devices 110 can communicate with each other via communication link 115 through AP 105, each wireless device 110 can also communicate directly with one or more other wireless devices 110 via direct wireless link 120. Two or more wireless devices 110 can communicate via direct wireless link 120 when both wireless devices 110 are within the geographical coverage area 125 of the AP, or when one or both wireless devices 110 are not within the geographical coverage area 125 of the AP. Examples of direct wireless link 120 may include Wi-Fi direct connection, connection established using a Wi-Fi Tunnel Direct Link Establishment (TDLS) link, 5G-NR sidelink, PC5, and other P2P group connections. In these examples, the wireless device 110 can communicate according to a WLAN radio and baseband protocol, which includes physical and MAC layers from IEEE 802.11 and its various versions, including but not limited to 802.11b, 802.11g, 802.11a, 802.11n, 802.11ac, 802.11ad, 802.11ah, 802.11ax, etc. In other implementations, other peer-to-peer connections and / or ad hoc networks can be implemented within the WLAN network 100.

[0032] Also refer to Figure 2UE 200 is an example of wireless device 110 and includes a computing platform comprising a processor 210, a memory 211 including software (SW) 212, one or more sensors 213, a transceiver interface 214 for a transceiver 215, a user interface 216, a satellite positioning system (SPS) receiver 217, a camera 218, and a positioning (motion) device 219. The processor 210, memory 211, sensors 213, transceiver interface 214, user interface 216, SPS receiver 217, camera 218, and positioning (motion) device 219 can be communicatively coupled to each other via a bus 220 (which can be configured for, for example, optical and / or electrical communication). One or more of the illustrated devices (e.g., camera 218, positioning (motion) device 219, and / or one or more sensors 213, etc.) may be omitted from UE 200. The processor 210 may include one or more intelligent hardware devices, such as a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), etc. Processor 210 may include multiple processors, including a general-purpose / application processor 230, a digital signal processor (DSP) 231, a modem processor 232, a video processor 233, and / or a sensor processor 234. One or more of processors 230-234 may include multiple devices (e.g., multiple processors). For example, sensor processor 234 may include processors for radio frequency (RF) sensing and ultrasound. Modem processor 232 may support dual SIM / dual connectivity (or even more SIMs). For example, one SIM (Subscriber Identity Module) may be used by an original equipment manufacturer (OEM), while another SIM may be used by the end user of UE 200 for connectivity. Memory 211 is a non-transitory storage medium that may include random access memory (RAM), flash memory, disk storage, and / or read-only memory (ROM), etc. Memory 211 stores software 212, which may be processor-readable, processor-executable software code containing instructions configured to cause processor 210 to perform the various functions described herein when executed. Alternatively, software 212 may not be executed directly by processor 210, but may be configured to cause processor 210, for example, to perform these functions during compilation and execution. This description may refer only to processor 210 performing the functions, but it includes other implementations such as processor 210 executing software and / or firmware. This description may refer to processor 210 performing the functions as an abbreviation for one or more processors 230-234 performing the functions. This description may refer to UE 200 performing the functions as an abbreviation for one or more appropriate components of UE 200 performing the functions. In addition to and / or instead of memory 211, processor 210 may include memory with stored instructions. The functionality of processor 210 will be discussed more fully below.

[0033] Figure 2 The configuration of UE 200 shown is an example of the invention and not a limitation thereof, including the claims, and other configurations may be used. For example, an example configuration of the UE includes one or more of processors 230-234 of processor 210, memory 211, and wireless transceiver 240. Other example configurations include one or more of processors 230-234 of processor 210, memory 211, wireless transceiver 240, and one or more of sensors 213, user interface 216, SPS receiver 217, camera 218, PMD 219, and / or wired transceiver 250. Other configurations may not include all components of UE 200. For example, an IoT device may include one or more wireless transceivers 240, memory 211, and processor 230.

[0034] UE 200 may include a modem processor 232 capable of performing baseband processing on signals received and down-converted by transceiver 215 and / or SPS receiver 217. Modem processor 232 may also perform baseband processing on signals to be up-converted for transmission by transceiver 215. Similarly or alternatively, baseband processing may be performed by processor 230 and / or DSP 231. However, other configurations may be used to perform baseband processing.

[0035] UE 200 may include sensor 213, which may include, for example, an inertial measurement unit (IMU) 270, one or more magnetometers 271, and / or one or more environmental sensors 272. IMU 270 may include one or more inertial sensors, such as one or more accelerometers 273 (e.g., collectively responding to accelerations in three-dimensional directions of UE 200) and / or one or more gyroscopes 274. The magnetometers may provide measurements to determine orientation (e.g., relative to magnetic north and / or true north), which can be used for any of a variety of purposes, such as supporting one or more compass applications. Environmental sensors 272 may include, for example, one or more temperature sensors, one or more atmospheric pressure sensors, one or more ambient light sensors, one or more camera imagers, and / or one or more microphones, etc. Sensor 213 may generate analog and / or digital signals, the indications of which may be stored in memory 211 and processed by DSP 231 and / or processor 230 to support one or more applications, such as, for example, applications for positioning and / or navigation operations.

[0036] Sensor 213 can be used for relative position measurement, relative position determination, motion determination, etc. Information detected by sensor 213 can be used for motion detection, relative displacement, dead reckoning, sensor-based position determination, and / or sensor-assisted position determination. Sensor 213 can be used to determine whether UE 200 is stationary or moving. In another example, for relative positioning information, the sensor / IMU can be used to determine the angle and / or orientation of other devices relative to UE 200, etc.

[0037] IMU 270 can be configured to provide measurements of the direction and / or velocity of motion of UE 200, which can be used for relative position determination. For example, one or more accelerometers 273 and / or one or more gyroscopes 274 of IMU 270 can detect the linear acceleration and rotational velocity of UE 200, respectively. The linear acceleration and rotational velocity measurements of UE 200 can be integrated over time to determine the instantaneous direction and displacement of UE 200. The instantaneous direction and displacement of motion can be integrated to track the position of UE 200. For example, the reference position of UE 200 at a certain moment can be determined, for example, using SPS receiver 217 (and / or by some other means), and measurements from accelerometers 273 and gyroscopes 274 taken after that moment can be used in dead reckoning to determine the current position of UE 200 based on the movement (direction and distance) of UE 200 relative to the reference position.

[0038] Magnetometer 271 can determine the magnetic field strength in different directions, which can be used to determine the orientation of UE 200. For example, the orientation can be used to provide a digital compass for UE 200. Magnetometer 271 may include a two-dimensional magnetometer configured to detect and provide an indication of magnetic field strength in two orthogonal dimensions. Similarly or alternatively, magnetometer 271 may include a three-dimensional magnetometer configured to detect and provide an indication of magnetic field strength in three orthogonal dimensions. Magnetometer 271 may provide components for sensing the magnetic field and providing an indication of the magnetic field to, for example, processor 210.

[0039] Transceiver 215 may include a wireless transceiver 240 and a wired transceiver 250, configured to communicate with other devices via wireless and wired connections, respectively. For example, wireless transceiver 240 may include a transmitter 242 and a receiver 244 coupled to one or more antennas 246 for transmitting and / or receiving wireless signals 248, and converting signals from wireless signals 248 into wired (e.g., electrical and / or optical) signals, and from wired (e.g., electrical and / or optical) signals into wireless signals 248. Therefore, transmitter 242 may include multiple transmitters, which may be discrete components or combined / integrated components, and / or receiver 244 may include multiple receivers, which may be discrete components or combined / integrated components. The wireless transceiver 240 can be configured to communicate signals (e.g., with an access point and / or one or more other devices) according to various radio access technologies (RATs), such as IEEE 802.11 (including IEEE 802.11ax), WiFi, WiFi Direct (WiFi-D), etc. Zigbee, etc. Wired transceiver 250 may include a transmitter 252 and a receiver 254 configured for wired communication. Transmitter 252 may include multiple transmitters, which may be discrete components or combined / integrated components, and / or receiver 254 may include multiple receivers, which may be discrete components or combined / integrated components. Wired transceiver 250 may be configured, for example, for optical communication and / or electrical communication. Transceiver 215 may be communicatively coupled to transceiver interface 214, for example, via optical and / or electrical connections. Transceiver interface 214 may be at least partially integrated with transceiver 215.

[0040] User interface 216 may include one or more of several devices, such as, for example, a speaker, microphone, display device, vibration device, keyboard, touchscreen, etc. User interface 216 may include more than one of these devices. User interface 216 may be configured to enable a user to interact with one or more applications hosted by UE 200. For example, user interface 216 may store indications of analog and / or digital signals in memory 211 for processing by DSP 231 and / or general-purpose processor 230 in response to actions from the user. Similarly, applications hosted on UE 200 may store indications of analog and / or digital signals in memory 211 to present output signals to the user. User interface 216 may include audio input / output (I / O) devices, including, for example, speakers, microphones, digital-to-analog circuitry, analog-to-digital circuitry, amplifiers, and / or gain control circuitry (including more than one of these devices). Other configurations of the audio I / O devices may be used. Similarly or alternatively, user interface 216 may include one or more touch sensors that respond to, for example, touch and / or pressure on the keyboard and / or touchscreen of user interface 216.

[0041] SPS receiver 217 (e.g., a Global Positioning System (GPS) receiver) is capable of receiving and acquiring SPS signal 260 via SPS antenna 262. Antenna 262 is configured to convert the wireless signal 260 into a wired signal, such as an electrical signal or an optical signal, and may be integrated with antenna 246. SPS receiver 217 may be configured to process the acquired SPS signal 260, in whole or in part, to estimate the location of UE 200. For example, SPS receiver 217 may be configured to determine the location of UE 200 using trilateration with SPS signal 260. In conjunction with SPS receiver 217, general-purpose processor 230, memory 211, DSP 231, and / or one or more dedicated processors (not shown) may be used to process the acquired SPS signal, in whole or in part, and / or calculate the estimated location of UE 200. Memory 211 may store indications (e.g., measurements) of SPS signal 260 and / or other signals (e.g., signals acquired from wireless transceiver 240) for use in performing positioning operations. A general-purpose processor 230, a DSP 231, and / or one or more dedicated processors and / or a memory 211 can provide or support a position engine for use in processing measurements to estimate the position of the UE 200.

[0042] UE 200 may include a camera 218 for capturing still or moving images. Camera 218 may include, for example, an imaging sensor (e.g., a charge-coupled device or a CMOS imager), a lens, analog-to-digital circuitry, a frame buffer, etc. General-purpose processor 230 and / or DSP 231 may perform additional processing, conditioning, encoding, and / or compression on the signals representing the captured images. Similarly or alternatively, video processor 233 may perform conditioning, encoding, compression, and / or manipulation on the signals representing the captured images. Video processor 233 may decode / decompress stored image data for presentation on a display device (not shown) (e.g., user interface 216).

[0043] The Positioning (Motion) Device (PMD) 219 can be configured to determine the location and possible motion of the UE 200. For example, the PMD 219 can communicate with, and / or include, some or all of the SPS receivers 217. The PMD 219 can also, or alternatively, be configured to determine the location of the UE 200 using land-based signals (e.g., at least some of signals 248), for trilateration, to assist in acquiring and using SPS signals 260, or both. The PMD 219 can be configured to determine the location of the UE 200 using one or more other techniques (e.g., relying on the UE's self-reported location (e.g., part of the UE's location beacon)), and can use a combination of techniques (e.g., SPS and land-based positioning signals) to determine the location of the UE 200. PMD 219 may include one or more sensors 213 (e.g., gyroscope, accelerometer, magnetometer, etc.) that can sense the orientation and / or motion of UE 200 and provide indications thereof. Processor 210 (e.g., processor 230 and / or DSP 231) may be configured to determine the motion of UE 200 (e.g., velocity vector and / or acceleration vector). PMD 219 may be configured to provide indications of uncertainty and / or error in the determined positioning and / or motion.

[0044] Also refer to Figure 3An example of an access point (AP) 300 (such as AP 105) includes a computing platform comprising a processor 310, a memory 311 including software (SW) 312, a transceiver 315, and (optionally) an SPS receiver 317. The processor 310, memory 311, transceiver 315, and SPS receiver 317 can be communicatively coupled to each other via a bus 320 (which can be configured for, for example, optical and / or electrical communication). One or more of the illustrated devices (e.g., wireless interface and / or SPS receiver 317) may be omitted from the AP 300. The SPS receiver 317 may be configured similarly to SPS receiver 217 to be able to receive and acquire SPS signal 360 via SPS antenna 362. The processor 310 may include one or more intelligent hardware devices, such as a central processing unit (CPU), microcontroller, application-specific integrated circuit (ASIC), etc. The processor 310 may include multiple processors (e.g., including general-purpose / application processors, DSPs, modem processors, video processors, and / or sensor processors, such as… Figure 2 (As shown). Memory 311 is a non-transitory storage medium, which may include random access memory (RAM), flash memory, disk storage, and / or read-only memory (ROM), etc. Memory 311 stores software 312, which may be processor-readable and processor-executable software code containing instructions configured to cause processor 310 to perform the various functions described herein when executed. Alternatively, software 312 may not be executed directly by processor 310, but may be configured to cause processor 310, for example, to perform these functions when compiled and executed. This description may refer only to processor 310 that performs the functions, but this includes other implementations, such as processor 310 performing software and / or firmware. This description may refer to processor 310 that performs the functions as an abbreviation for one or more processors included in processor 310 that performs the functions. In addition to and / or instead of memory 311, processor 310 may include memory with stored instructions. The functionality of processor 310 will be discussed more fully below.

[0045] Transceiver 315 may include a wireless transceiver 340 and a wired transceiver 350, configured to communicate with other devices via wireless and wired connections, respectively. For example, wireless transceiver 340 may include a transmitter 342 and a receiver 344 coupled to one or more antennas 346 for transmitting (e.g., on one or more uplink channels) and / or receiving (e.g., on one or more downlink channels) wireless signals 348, and converting signals from wireless signals 348 into wired (e.g., electrical and / or optical) signals, and from wired (e.g., electrical and / or optical) signals into wireless signals 348. Therefore, transmitter 342 may include multiple transmitters, which may be discrete components or combined / integrated components, and / or receiver 344 may include multiple receivers, which may be discrete components or combined / integrated components. The wireless transceiver 340 can be configured to communicate signals according to various radio access technologies (RATs) (e.g., with UE 200, one or more other UEs, and / or one or more other devices), such as IEEE 802.11 (including IEEE 802.11ax), WiFi, WiFi Direct (WiFi-D), etc. Zigbee, etc. The wired transceiver 350 may include a transmitter 352 and a receiver 354 configured for wired communication. The transmitter 352 may include multiple transmitters, which may be discrete components or combined / integrated components, and / or the receiver 354 may include multiple receivers, which may be discrete components or combined / integrated components. The wired transceiver 350 may be configured, for example, for optical communication and / or electrical communication.

[0046] refer to Figure 4 The diagram 400 illustrates a concept diagram of radio frequency sensing for concurrent transmission and reception by a wireless device. Wireless devices such as UE200 or AP 300 include transceivers 240 and 340, which have multiple transmit and receive chains configured for concurrent transmission and reception of RF signals. Figure 4The number of transmit and receive chains is merely an example and not a limitation, as other transceiver and antenna configurations can be used. For example, transceiver 240 can be configured for multiple-input multiple-output (MIMO) with two transmit chains and two receive chains. Other array sizes and configurations can be used. In one example, transceiver 240 may include a transmit chain comprising a transmit antenna 402 operatively coupled to a transmit RF module 408. The transmit RF module 408 is configured to receive a signal from a digital-to-analog converter (DAC) 406 and transmit a corresponding RF signal via the transmit antenna 402. This signal may be generated by a processor such as a modem processor 232 and / or an application processor 230. Transceiver 240 may include one or more receive chains comprising a receive antenna 404, a receive RF module 416, and an analog-to-digital converter (ADC) 414. Additional receive modules, such as a second receive chain 420 and a third receive chain 422, may also be used.

[0047] In operation, the wireless device can transmit an RF signal 412a to a target 418. A reflected signal 412b is the portion of the RF signal 412a reflected by the target 418 and received by one or more receiving antennas (such as receiving antenna 404). An additional receiver chain can implement beamforming / direction detection to enable the wireless device to calculate the angle of arrival (AoA) of the received signal. The receiver chain can also receive a transmission leakage signal 410 simultaneously with the transmission of the RF signal 412a. Depending on the configuration of the wireless device, the transmission leakage 410 can be conducted and / or radiated interference. For example, physical shielding can be used to reduce radiated interference between the transmitting and receiving antennas. In one embodiment, the RF signal 412a can be a pre-designed sequence of length “L”. The pre-designed sequence can be designed to have cyclic autocorrelation properties, such as a single-carrier Zadoff-Chu sequence, or similar symbols as in Orthogonal Frequency Division Multiplexing (OFDM). This sequence can be repeated and transmitted consecutively “n” times, allowing the receiver chain of the wireless device to begin listening for a length “L” to receive the sequence at a later time without losing signal information. This relaxed timing requirement for the receiver chain means that it does not have to start at the same time as the transmitter.

[0048] The receiving RF module 416 (and the additional receiving chains 420, 422) can listen to and receive "m" sequences instead of one sequence. For example, the receiving RF module 416 can listen to a length of m*L, where "m" is the number of sequences captured by the receiving RF module 416, and m ≤ n. The UE 200 can combine the received "m" sequences to improve the signal-to-noise ratio (SNR). The received sequences can be used for RF sensing. For example, a channel estimate based on signal correlation techniques can be obtained using known transmitted sequences. The channel estimate can be processed via an iterative cancellation algorithm to detect leakage and reflection. The time difference between leakage and reflection can be used to estimate the distance to the target 418. Multiple Rx antennas, such as the additional receiving chains 420, 422, can be used to receive sequences in the reflected signal 412b, determine the channel estimate, and obtain an angle estimate of the reflected signal 412b. Changes in the channel estimate can be used to detect motion of the target 418. Classification algorithms and / or machine learning of the channel estimate results can be used to identify the motion type and / or size of the target 418. In one example, channel estimation can be used to detect attitude changes of target 418.

[0049] Figure 4 The number of transmit and receive chains on the wireless device shown is merely an example and not a limitation. Other wireless devices may have multiple arrays, and each array may include different numbers and patterns of antenna elements. For example, antenna arrays may include matrices of elements such as 1×2, 1×4, 1×5, 1×8, 2×2, 2×4, 2×5, 2×8, 3×4, 3×5, 3×8, etc. Other antenna array matrix dimensions may also be used.

[0050] In one embodiment, a wireless device having one or more multi-element antenna arrays can be configured to perform beamforming on transmitted and received RF signals. For example, transceiver 240 may include a radio frequency integrated circuit (RFIC) that includes a phase shifter to modify the transmitted and received beam gain. The wireless device can be configured to change the angle of departure (AoD) of the RF signal 412a. In one example, the RF signal 412a may sweep across different AoDs, and the gain of the corresponding reflected signal can be determined. Changing the AoD of the RF signal 412a can be used to determine a direct path to target 418 (e.g., based on the highest reflection gain). In one example, beam sweeping can be used to determine the changing attitude of the object (e.g., based on a series of reflected signals over time). In one embodiment, the transmitted RF signal 412a may be a polarized signal, and the polarization of the received signal 412b can be detected. The polarization change between the transmitted and received signals can be used to determine characteristics and / or classify target 418.

[0051] refer to Figure 5 And further reference Figure 4 Figure 500 illustrates an example received signal. Figure 500 includes a relative power axis 502, a time axis 504, and a signal response function 506. The signal response function 506 represents the signal detected by the receiving antenna 404. A first peak 508 is based on transmission leakage 410, and a second peak 510 is based on reflected signal 412b. The RF receiver 416 (and other receiver chains 420, 422) can be configured to reduce the receive gain during the transmission period of the RF signal 412a. For example, one or more amplifier components in the receiver (e.g., a low-noise amplifier (LNA)) can be configured with adjustable gain functionality. The receive gain can be reduced to mitigate the effect of leakage on the receiver chain. Other iterative cancellation algorithms can be used to reduce the effect of the first peak 508 and improve the detection of the second peak 510. The transmit gain of the RF transmitting module 408 can be increased to improve the detection of reflected signal 412b. For example, the transmit gain can be iteratively increased for each sequence based on the values ​​of one or more peaks associated with reflected signal 412b.

[0052] In operation, the signal response function 506 includes the transmission sequence, and the corresponding ADC capture in the ADC module 414 is equivalent to channel capture, which can be used to implement RF sensing use cases based on channel capture. The time difference between the first peak 508 (i.e., transmission time) and the second peak 510 (i.e., reflected signal 412b) can be used to estimate the distance to the target 418. The AoA of the reflected signal 412b can be obtained based on ADC captures from multiple antennas (e.g., additional receive chains 420, 422). The measured distance and direction information to the target 418 can be used for indoor mapping applications. The bandwidth of the transmitted RF signal 412a can vary and is not limited to Wi-Fi packet bandwidth. For example, a wide bandwidth can be based on DAC and ADC rates, and analog filter bandwidth that may be greater than the Wi-Fi packet bandwidth. The transmission and reception of the RF signal 412a can be performed within hundreds of microseconds, so the impact on Wi-Fi communication can be minimal. Therefore, the RF sensing techniques described herein can be used simultaneously with Wi-Fi data exchange functionality.

[0053] refer to Figure 6 The diagram 600 illustrates a concept diagram of in-chain transmission and reception for a wireless device. Wireless devices such as UE 200 or AP 300 include transceivers 602 having one or more transmission and reception chains. Figure 6The number of transmit and receive chains is merely an example and not a limitation, as other transceiver and antenna configurations can be used. For example, transceiver 602 can be configured for multiple-input multiple-output (MIMO) with two transmit chains and two receive chains. Other array sizes and configurations can be used. Generally, transmit and receive chains are conceptual terms referring to the hardware necessary for transmitting / receiving signal processing. MIMO radios can be configured to add signal components from multiple antennas. Single-chain transmit and receive operation can utilize a single antenna for both transmit and receive functions. In one example, the first transceiver chain 604 is configured for single-chain Tx and Rx operation. Transceiver 602 may include additional transceiver chains 606a, 606b configured for single-chain or independent Tx and Rx operation. The first transceiver chain 604 is configured to transmit RF signal 608a to target 610 and then receive reflected RF signal 608b. For example, the first transceiver chain 604 can be configured to switch between ports of a directional coupler to achieve in-chain Tx and Rx operation. In one embodiment, additional transceiver chains 606a and 606b can also receive their respective reflected signals 608c and 608d. RF signal 608a can be a single-carrier Zadoff-Chu sequence or orthogonal frequency division multiplexing (OFDM) symbols or other orthogonal resources, configured to optimize synchronization and channel estimation performance, such as... Figure 4 As described in [the document]. In one example, a wireless device can improve channel information acquisition by utilizing multiple Tx and multiple Rx using MIMO, such as by using existing MIMO preamble long training field (LTF) sequences. Other sequences and signals can also be used.

[0054] refer to Figure 7 And further reference Figures 1-6 A method 700 for setting the transmit gain for radio frequency sensing includes the stages shown. Typically, method 700 can be used to set the transmit gain of an RF signal to increase the Received Signal Strength Indication (RSSI) while reducing receiver saturation. However, method 700 is merely an example and not a limitation. Method 700 can be modified, for example, by adding, removing, rearranging, combining, or performing simultaneously stages, and / or dividing a single stage into multiple stages.

[0055] At stage 702, the method includes setting a first transmit gain to avoid receiver saturation. Transmit RF module 408 is the component used to set the first transmit gain. Transceivers in wireless devices such as UE 200 and AP 300 can be configured to modify the output gain (e.g., adjust Tx power) of one or more transmitter chains such as transmit RF module 408. RF module 408 can transmit a first RF signal with a sufficiently safe low transmit gain (e.g., TxGain_1) to avoid receiver saturation. Receiver saturation can be determined based on the amount of signal clipping observed in the received signal. The value of TxGain_1 can be selected such that the received signal is not distorted due to clipping or other attenuation caused by signal saturation. In one example, the value of TxGain_1 can be stored in memory and used for initial transmissions in an RF sensing application.

[0056] In stage 704, the method includes transmitting a first signal using a first transmit gain. Transmit RF module 408 is a component for transmitting the first signal using the first transmit gain. For example, refer to... Figure 4 The first signal can be RF signal 412a. The first signal can be a first Wi-Fi RF sensing packet, or other RF signals, such as a single-carrier Zadoff-Chu sequence, or a symbol similar to an OFDM LTF.

[0057] At stage 706, the method includes receiving the reflection of the first signal and estimating a transmit gain adjustment value. The receive RF module 416 is a component for receiving the reflection of the first signal, and the processor 230 may be a component for estimating the transmit gain adjustment value. (See reference...) Figure 4 The reflected signal can be reflected signal 412b. In one example, processor 230 or another processor in the wireless device can be configured to determine the remaining headroom in ADC 414 based on the first signal. The headroom can be based on the amplitude of a time-varying signal (e.g., a peak value of a sine wave) or the clipping level in a quadrature signal (e.g., a symbol similar to OFDM). The increase in transmit gain can be based on the available remaining headroom. The transmit gain adjustment can be the value TX Gain_delta, which represents an estimate of the increase in transmit gain to improve RSSI without saturating the receiver.

[0058] At stage 708, the method includes transmitting a second signal using a transmit gain adjustment value. The transmit RF module 408 is a component for transmitting the second signal. The transmit RF module 408 can transmit another Wi-Fi RF sensing packet, or another RF signal having a transmitter gain equal to the first transmit gain (i.e., TxGain_1) plus the transmit gain adjustment value (i.e., TX Gain_delta). Therefore, the signal can have a transmit gain value TxGain_2 = TxGain_1 + TX Gain_delta.

[0059] In stage 710, the method includes receiving the reflection of the second signal and estimating a transmit gain adjustment value. The receive RF module 416 is a component for receiving the second signal, and the processor 230 may be a component for estimating the transmit gain adjustment value. In one example, the processor 230 or another processor in the wireless device may be configured to determine the remaining headroom in the ADC 414 based on the signal transmitted in stage 708 (e.g., transmit gain in the form of TxGain_2). As previously described, the processor 230 may be configured to adjust the transmit gain adjustment value based on the amplitude of a time-varying signal (e.g., a sine wave peak) or the clipping level in a quadrature signal (e.g., an OFDM-like symbol). The transmit gain value can be adjusted, and the process can iteratively return to stage 708 based on the adjusted transmit gain value on an additional signal.

[0060] Method 700 can be used to set the transmit gain value when the wireless device is initialized and the Wi-Fi RF sensing capability is activated. Method 700 can also be executed periodically or based on trigger conditions (such as detecting a change in location, a change in the surrounding environment, or a hardware or software change). Other trigger conditions, such as abnormal RSSI values ​​or when ADC clipping is detected, can also be used to initialize Method 700.

[0061] refer to Figure 8 And further reference Figures 1-6 A method 800 for setting the receiver gain for radio frequency sensing includes the stages shown. Typically, method 800 can be used to set the receiver gain of an RF signal to improve ADC range, reduce quantization noise and clipping, and improve weak signal detection. However, method 800 is merely an example and not a limitation. Method 800 can be modified, for example, by adding, removing, rearranging, combining, or performing concurrently stages, and / or dividing a single stage into multiple stages.

[0062] At stage 802, the method includes setting a first receiver gain and receiving a first signal. The receiving RF module 416 is a component for setting the first receiver gain and receiving the first signal. The first receiver gain value (i.e., RxGain_1) may be a preset value stored in memory and set when the receiving RF module 416 is initialized. The first signal may be a reflected signal 412b including a first Wi-Fi RF sensing packet, or other RF signals such as a single-carrier Zadoff-Chu sequence, or a symbol similar to an OFDM LTF.

[0063] At stage 804, the method includes estimating a reduced receiver gain value. Processor 230 may be a component used to estimate the reduced receiver gain value. In one example, processor 230 or another processor in the wireless device may be configured to determine the degree of clipping of the received signal occurring in ADC 414. Clipping may be based on the expected amplitude of a time-varying signal (e.g., a sine wave peak) or the clipping level of resources in a quadrature signal (e.g., OFDM-like symbols). The receiver gain may be a reduction value RX Gain_delta, which represents a proportional reduction in receiver gain based on the ADC range and the clipping level in the received signal. A first receiver gain reduction estimate (i.e., RxGain_2 = RxGain_1 - RX Gain_delta).

[0064] In stage 806, the method includes receiving a second signal using a reduced receiver gain. The receive RF module 416 is a component for receiving the second signal. The second signal may be another reflected signal 412b including a second Wi-Fi RF sensing packet, or another RF signal such as those previously described. Method 800 may iterate back to stage 804 to determine whether the receive gain value requires additional adjustment based on the signal quality in ADC 414. Method 800 can be used to set the receiver gain value when the wireless device is initialized and the Wi-Fi RF sensing capability is activated. Method 800 may also be executed periodically or based on triggering conditions such as the detection of a location change, a change in the surrounding environment, or a hardware or software change. Other triggering conditions, such as abnormal RSSI values ​​or when ADC clipping is detected, may also be used to initialize method 800.

[0065] In operation, wireless devices can be configured to clear the channel before transmitting RF sensing signals to avoid collisions with other Wi-Fi frames. In one example, the device can send a Clear Transmit (CTS) to itself on the same bandwidth as the RF sensing signal to clear the channel. In another example, the device can transmit an existing Wi-Fi legacy preamble format to ensure other devices comply with the RF sensing signal. In yet another example, the device is configured to transmit the RF sensing signal within a Short Frame Interval (SIFS) after transmission or after the end of a received packet. Other methods can also be used to verify channel clearance.

[0066] refer to Figure 9 And further reference Figures 1-8 A method 900 for controlling a receiver for radio frequency sensing in a wireless device includes the stages shown. However, method 900 is merely an example and not a limitation. Method 900 can be modified, for example, by adding, removing, rearranging, combining, performing simultaneously, and / or dividing a single stage into multiple stages.

[0067] At stage 902, the method includes setting a first level of receive gain on a wireless device. RF receiver module 416 is a component for setting the receive gain to the first level. In one example, a wireless device such as UE 200 or AP 300 is configured to reduce the gain on one or more receive chains during a period of transmitting an RF sensing signal. For example, RF receiver 416 (and other receive chains 420, 422) may be configured to reduce the receive gain during the transmission of RF signal 412a. In one embodiment, one or more amplifier components (e.g., LNAs) in the receiver may be configured with adjustable gain functionality and may reduce the receive gain to mitigate the effects of leakage on the receive chain.

[0068] In stage 904, the method includes transmitting a radio frequency (RF) signal using a wireless device at a first moment, wherein the wireless device receives a leaked signal with a first level of receive gain. The RF transmission module 408 is a component for transmitting the RF signal. (See reference...) Figure 4 The leaked signal can be a leaked signal 410 received simultaneously with the transmission of the RF signal. In one example, the RF signal can be a pre-designed sequence with cyclic autocorrelation properties, such as a single-carrier Zadoff-Chu sequence or OFDM-like symbols. The first time can be based on the time when an RF signal in the sequence is transmitted. The sequence can be repeated and transmitted consecutively "n" times, so that the receiver chain of UE 200 or AP 300 can start listening for a length "L" to receive the sequence at a later time without losing signal information. In one embodiment, method 700 can be used to set the transmitter gain of the RF signal.

[0069] In stage 906, the method includes setting the receive gain on the wireless device to a second level. The receive RF module 416 is a component for setting the receive gain to the second level. Compared to the first level, the second level may involve an increase in the receiver gain. That is, the LNA in the receive gain can be configured to increase the sensitivity for detecting the reflected signal 412b. The increase in receiver gain is transmitted after the transmission in stage 904. In one embodiment, method 800 may be used to set the value of the second receive gain level.

[0070] At stage 908, the method includes receiving a reflection of a radio frequency (RF) signal at a second time using a wireless device, wherein the reception gain is at a second level. A receiving RF module 416 is a component for receiving the reflected RF signal. The reflected RF signal received at the second time may be a reflected RF signal 412b and may be received by one or more receiving chains (e.g., additional receiving chains 420, 422). In one example, the receiving RF module 416 may use an increased Rx gain value of a second peak 510 received at the second time for listening. The receiving RF module 416 may also listen to and receive “m” sequences instead of one sequence. For example, the receiving RF module 416 may listen to a length of m*L, where “m” is the number of sequences captured by the receiving RF module 416, and m ≤ n. The wireless device may combine the received “m” sequences to improve the signal-to-noise ratio (SNR) of the reflected signal.

[0071] In stage 910, the method includes determining the distance to an object based at least in part on the difference between a first time and a second time. Processor 230 in UE 200 and processor 310 in AP 300 are components used to determine the distance. The difference between the transmission time (i.e., the first time) and the reception time (i.e., the second time) represents the round-trip flight time of the transmitted signal 412a and the reflected signal 412b. In one example, the distance can be calculated as half the time difference multiplied by the speed of light. Other error corrections and bias values ​​may also be used in the distance calculation. Additional values ​​such as RSSI and AoA can be used to determine the distance, direction, and orientation of the target.

[0072] refer to Figure 10 And further reference Figures 1-8 The method 1000 for determining the distance to an object using radio frequency sensing includes the stages shown. However, method 1000 is merely an example and not a limitation. Method 1000 can be modified, for example, by adding, removing, rearranging, combining, performing simultaneously on the stages, and / or dividing a single stage into multiple stages.

[0073] In phase 1002, the method includes transmitting a radio frequency (RF) signal using a transmission channel on a wireless device. The RF transmission module 408 is a component for transmitting the RF signal. The RF signal may be one or more Wi-Fi packets or other RF signals transmitted from one or more transmission antennas 402. Generally, a Wi-Fi packet is a term for electronic data transmission in a Wi-Fi network. In one embodiment, the wireless device may be configured to transmit multiple RF signals from one or more transmitters and transmission antennas. In one example, the RF signal may be a pre-designed sequence with cyclic autocorrelation properties, such as a single-carrier Zadoff-Chu sequence or similar OFDM LTF symbols. The first time may be based on the time when one RF signal in the sequence is transmitted. The sequence may be repeated and transmitted consecutively "n" times, such that the receiver chain of UE 200 or AP 300 can begin listening for a length "L" to receive the sequence at a later time without losing signal information. In one embodiment, the transmitter gain of the RF signal may be determined based on method 700 and stored in memory for use when an RF sensing application is activated.

[0074] In stage 1004, the method includes receiving a leaked signal on the device using a receiving channel at a first time, wherein the leaked signal is based on a radio frequency (RF) signal. The receiving RF module 416 is a component for receiving the leaked signal. In one example, in stage 1002, one or more receiving chains in the wireless device may receive the transmission leaked signal 410 while transmitting an RF signal. Depending on the configuration of the wireless device, the transmission leak 410 may be conducted and / or radiated interference. The wireless device is configured to determine the time at which one or more RF leaked signals are received. The leaked signal may be received on more than one receiving chain and at the time of the TX leakage peak (e.g., a first peak 508).

[0075] In stage 1006, the method includes receiving a reflected signal on the device using a receiving channel at a second time, wherein the reflected signal is based on a radio frequency signal reflected from an object. A receiving RF module 416 is a component for receiving the reflected signal. The radio frequency signal received at the second time may be the reflected RF signal 412b and may be received by one or more receiving chains (e.g., additional receiving chains 420, 422). In one example, the receiving RF module 416 may listen to and receive “m” sequences instead of one sequence. For example, the receiving RF module 416 may listen to a length of m*L, where “m” is the number of sequences captured by the receiving RF module 416, and m ≤ n. The wireless device may combine the received “m” sequences to improve the signal-to-noise ratio (SNR) of the reflected signal. In one embodiment, a receiver gain for receiving the RF signal may be determined based on method 800 and stored in memory for use when an RF sensing application is activated.

[0076] In stage 1008, the method includes determining the distance to an object based at least in part on the difference between a first time and a second time. Processor 230 in UE 200 and processor 310 in AP 300 are components used to determine the distance. The difference between the time of receiving the leaked signal (i.e., the first time) and the time of receiving it (i.e., the second time) represents the round-trip flight time of the transmitted signal 412a and the reflected signal 412b. In one example, the distance can be calculated as half the time difference multiplied by the speed of light. Other error corrections and bias values ​​can also be used in the distance calculation. Additional values ​​such as RSSI and AoA can be used to determine the target's distance, azimuth, and orientation.

[0077] In one embodiment, method 1000 may include one or more additional features. For example, the radio frequency (RF) signals may be a pre-defined sequence. Single-carrier Zadoff-Chu sequences, orthogonal frequency division multiplexing (OFDM) symbols, and one or more Wi-Fi packets are examples of pre-defined sequences. Multiple RF signals can be transmitted and received. Multiple RF signals can be transmitted using multiple transmit channels. Multiple RF signals can be received using multiple receive links. The angle of arrival (AoA) of the received RF signal and the angle of departure (AoD) of the transmitted signal can be determined. Transmitting and receiving RF signals can be performed using a single-chain transmit and receive operation.

[0078] Other examples and implementations are within the scope and spirit of this disclosure and the appended claims. For example, due to the nature of software and computers, the functions described above can be implemented using software, hardware, firmware, hardwired, or any combination thereof executed by a processor. Features implementing the functions can also be physically located in various locations, including being distributed such that portions of the functions are implemented in different physical locations.

[0079] As used herein, the singular forms “a,” “an,” and “the” also include the plural forms, unless the context clearly indicates otherwise. For example, “processor” can include one or more processors. The terms “comprising,” “including,” “containing,” and / or “including” as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0080] Similarly, as used herein, the “or” used in a list of items beginning with “at least one” or “one or more” indicates a separate list, such that, for example, a list of “at least one of A, B or C” or a list of “one or more of A, B or C” represents A or B or C or AB or AC or BC or ABC (i.e., A and B and C), or a combination having more than one feature (e.g., AA, AAB, ABBC, etc.).

[0081] Substantial changes can be made to meet specific requirements. For example, custom hardware can be used, and / or specific components can be implemented in hardware, processor-executed software (including portable software such as applets), or both. Furthermore, connections to other computing devices, such as network input / output devices, can be employed.

[0082] The systems and devices discussed above are examples. Various configurations may appropriately omit, substitute, or add various processes or components. For example, features described with reference to certain configurations may be combined in various other configurations. Different aspects and elements of configurations may be combined in a similar manner. Likewise, technology is evolving; therefore, many elements are illustrative and do not limit the scope of this disclosure or the claims.

[0083] A wireless communication system is a system that transmits communication wirelessly, that is, through electromagnetic waves and / or sound waves that propagate through the atmosphere, rather than through wired or other physical connections. A wireless communication network may not transmit all communications wirelessly, but is configured to transmit at least some communications wirelessly. Furthermore, the term "wireless communication device" or similar terms do not require that the device's function is exclusively or uniformly primarily for communication, or that the device is a mobile device, but rather indicate that the device includes wireless communication capabilities (one-way or two-way), for example, including at least one radio for wireless communication (each radio device is part of a transmitter, receiver, or transceiver).

[0084] Specific details are provided in the description to offer a comprehensive understanding of the example configuration (including its implementation). However, the configuration can be implemented without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail to avoid obscuring the configuration. This description provides only an example configuration and does not limit the scope, applicability, or configuration of the claims. Rather, the foregoing description of the configuration provides a description for implementing the described techniques. Various changes can be made to the function and arrangement of the elements without departing from the spirit or scope of this disclosure.

[0085] As used herein, the terms “processor-readable medium,” “machine-readable medium,” and “computer-readable medium” refer to any medium that participates in providing data that enables a machine to operate in a particular manner. Using a computing platform, various processor-readable media may involve providing instructions / code to a processor for execution, and / or may be used to store and / or carry such instructions / code (e.g., as signals). In many implementations, a processor-readable medium is a physical and / or tangible storage medium. Such media can take many forms, including but not limited to non-volatile and volatile media. Non-volatile media include, for example, optical discs and / or magnetic disks. Volatile media include, but are not limited to, dynamic memory.

[0086] A statement that a value exceeds (or is greater than or higher than) a first threshold is equivalent to a statement that the value reaches or exceeds a second threshold slightly greater than the first threshold, for example, in the resolution of a computing system, the second threshold is one value higher than the first threshold. A statement that a value is less than (or within or below) the first threshold is equivalent to a statement that the value is less than or equal to a second threshold slightly lower than the first threshold, for example, in the resolution of a computing system, the second threshold is one value lower than the first threshold.

[0087] Implementation examples are described in the following numbered clauses:

[0088] Clause 1. A method for determining the distance to an object using radio frequency sensing, comprising: transmitting a radio frequency signal on a wireless device using a transmit channel; receiving a leaked signal on the wireless device using a receive channel at a first time, wherein the leaked signal is based on the radio frequency signal; receiving a reflected signal on the wireless device using a receive channel at a second time, wherein the reflected signal is based on the radio frequency signal reflected from the object; and determining the distance to the object based at least in part on the difference between the first time and the second time.

[0089] Clause 2. The method according to Clause 1, wherein the radio frequency signals are a pre-specified sequence.

[0090] Clause 3. The method according to Clause 2, wherein the pre-specified sequence is a single-carrier Zadoff-Chu sequence.

[0091] Clause 4. The method according to Clause 2, wherein the pre-specified sequence includes orthogonal frequency division multiplexing symbols.

[0092] Clause 5. The method according to Clause 2, wherein the pre-specified sequence comprises one or more Wi-Fi packets.

[0093] Clause 6. The method according to Clause 1 further includes transmitting a plurality of radio frequency signals and receiving one or more of the plurality of radio frequency signals.

[0094] Clause 7. The method according to Clause 1 further includes transmitting multiple radio frequency signals using multiple transmission channels.

[0095] Clause 8. The method according to Clause 1, wherein receiving radio frequency signals includes receiving radio frequency signals using multiple receiving links.

[0096] Clause 9. The method according to Clause 8 further includes determining the angle of arrival of the received radio frequency signal.

[0097] Clause 10. The method according to Clause 1 further includes determining the departure angle of the radio frequency signal.

[0098] Clause 11. The method according to Clause 1, wherein transmitting and receiving radio frequency signals are performed using a single-chain transmit and receive operation.

[0099] Clause 12. An apparatus comprising: a memory; at least one transceiver including at least one transmit chain and at least one receive chain; at least one processor communicatively coupled to the memory and at least one transceiver, and configured to: transmit a radio frequency signal using at least one transmit chain; receive a leaked signal using at least one receive chain at a first time, wherein the leaked signal is based on the radio frequency signal; receive a reflected signal using at least one receive chain at a second time, wherein the reflected signal is based on the radio frequency signal reflected from an object; and determine a distance to an object based at least in part on the difference between the first time and the second time.

[0100] Clause 13. The apparatus pursuant to Clause 12, wherein the radio frequency signals are a pre-specified sequence.

[0101] Clause 14. The apparatus according to Clause 13, wherein the pre-specified sequence is a single-carrier Zadoff-Chu sequence.

[0102] Clause 15. The apparatus according to Clause 13, wherein the pre-specified sequence comprises orthogonal frequency division multiplexing symbols.

[0103] Clause 16. The apparatus pursuant to Clause 13, wherein the pre-specified sequence comprises one or more Wi-Fi packets.

[0104] Clause 17. The apparatus according to Clause 12, wherein at least one processor is further configured to transmit a plurality of radio frequency signals and receive one or more of the plurality of radio frequency signals.

[0105] Clause 18. The apparatus according to Clause 12, wherein at least one processor is further configured to transmit multiple radio frequency signals using multiple transmission chains.

[0106] Clause 19. The apparatus according to Clause 12, wherein at least one processor is further configured to receive radio frequency signals using a plurality of receive links.

[0107] Clause 20. The apparatus according to Clause 19, wherein at least one processor is further configured to determine the angle of arrival of the received radio frequency signal.

[0108] Clause 21. The apparatus according to Clause 12, wherein at least one processor is further configured to determine the departure angle of the radio frequency signal.

[0109] Clause 22. The apparatus according to Clause 12, wherein at least one processor is configured to transmit and receive radio frequency signals using single-chain transmit and receive operations.

[0110] Clause 23. An apparatus for determining the distance to an object using radio frequency sensing, comprising: means for transmitting a radio frequency signal on a wireless device using a transmission channel; means for receiving a leaked signal on the wireless device using a reception channel at a first time, wherein the leaked signal is based on the radio frequency signal; means for receiving a reflected signal on the wireless device using a reception channel at a second time, wherein the reflected signal is based on the radio frequency signal reflected from the object; and means for determining the distance to the object based at least in part on the difference between the first time and the second time.

[0111] Clause 24. The apparatus pursuant to Clause 23, wherein the radio frequency signals are a pre-specified sequence.

[0112] Clause 25. The apparatus pursuant to Clause 24, wherein the pre-specified sequence is a single-carrier Zadoff-Chu sequence.

[0113] Clause 26. The apparatus according to Clause 24, wherein the pre-specified sequence comprises orthogonal frequency division multiplexing symbols.

[0114] Clause 27. The apparatus pursuant to Clause 24, wherein the pre-specified sequence comprises one or more Wi-Fi packets.

[0115] Clause 28. The device pursuant to Clause 23 further includes components for transmitting a plurality of radio frequency signals and components for receiving one or more of the plurality of radio frequency signals.

[0116] Clause 29. The apparatus according to Clause 23 further includes components for transmitting multiple radio frequency signals using multiple transmission channels.

[0117] Clause 30. The apparatus pursuant to Clause 23, wherein the component for receiving radio frequency signals includes a component for receiving radio frequency signals using a plurality of receiving links.

[0118] Clause 31. The apparatus according to Clause 30 further includes a component for determining the angle of arrival of the received radio frequency signal.

[0119] Clause 32. The apparatus pursuant to Clause 23 further includes a component for determining the departure angle of the radio frequency signal.

[0120] Clause 33. The apparatus according to Clause 23, wherein the component for transmitting radio frequency signals and the component for receiving radio frequency signals are performed using a single-chain transmit and receive operation.

[0121] Clause 34. A non-transitory processor-readable storage medium comprising processor-readable instructions to cause one or more processors to determine a distance to an object using radio frequency sensing, the non-transitory processor-readable storage medium comprising: code for transmitting a radio frequency signal on a wireless device using a transmit channel; code for receiving a leaked signal on a wireless device using a receive channel at a first time, wherein the leaked signal is based on the radio frequency signal; code for receiving a reflected signal on a wireless device using a receive channel at a second time, wherein the reflected signal is based on the radio frequency signal reflected from the object; and code for determining a distance to the object based at least in part on the difference between the first time and the second time.

[0122] Clause 35. A non-transitory processor-readable storage medium pursuant to Clause 34, wherein the radio frequency signals are a pre-specified sequence.

[0123] Clause 36. A non-transitory processor-readable storage medium pursuant to Clause 35, wherein the pre-specified sequence is a single-carrier Zadoff-Chu sequence.

[0124] Clause 37. A non-transitory processor-readable storage medium pursuant to Clause 35, wherein a pre-specified sequence comprises orthogonal frequency division multiplexing symbols.

[0125] Clause 38. A non-transitory processor-readable storage medium pursuant to Clause 35, wherein the pre-specified sequence comprises one or more Wi-Fi packets.

[0126] Clause 39. The non-transitory processor-readable storage medium pursuant to Clause 34 further includes code for transmitting a plurality of radio frequency signals and code for receiving one or more of the plurality of radio frequency signals.

[0127] Clause 40. The non-transitory processor-readable storage medium pursuant to Clause 34 further includes code for transmitting multiple radio frequency signals using multiple transmission channels.

[0128] Clause 41. A non-transitory processor-readable storage medium pursuant to Clause 34, wherein the code for receiving radio frequency signals includes code for receiving radio frequency signals using multiple receive links.

[0129] Clause 42. The non-transitory processor-readable storage medium pursuant to Clause 41 further includes code for determining the angle of arrival of the received radio frequency signal.

[0130] Clause 43. The non-transitory processor-readable storage medium pursuant to Clause 34 further includes code for determining the departure angle of the radio frequency signal.

[0131] Clause 44. A method for setting a transmit gain for radio frequency sensing, comprising: setting a first transmit gain to avoid receiver saturation; transmitting a first signal using the first transmit gain; receiving a reflection of the first signal and estimating a transmit gain adjustment value; transmitting a second signal using the transmit gain adjustment value; and receiving a reflection of the second signal and estimating a transmit gain adjustment value.

[0132] Clause 45. An apparatus comprising: a memory; at least one transceiver including at least one transmit chain and at least one receive chain; at least one processor communicatively coupled to the memory and at least one transceiver, and configured to: set a first transmit gain to avoid receiver saturation; transmit a first signal using the first transmit gain; receive a reflection of the first signal and estimate a transmit gain adjustment value; transmit a second signal using the transmit gain adjustment value; and receive a reflection of the second signal and estimate a transmit gain adjustment value.

[0133] Clause 46. An apparatus for setting a transmit gain for radio frequency sensing, comprising: a component for setting a first transmit gain to avoid receiver saturation; a component for transmitting a first signal using the first transmit gain; a component for receiving a reflection of the first signal and estimating a transmit gain adjustment value; a component for transmitting a second signal using the transmit gain adjustment value; and a component for receiving a reflection of the second signal and estimating the transmit gain adjustment value.

[0134] Clause 47. A non-transitory processor-readable storage medium comprising processor-readable instructions to cause one or more processors to set a transmit gain for radio frequency sensing, the non-transitory processor-readable storage medium comprising: code for setting a first transmit gain to avoid receiver saturation; code for transmitting a first signal using the first transmit gain; code for receiving a reflection of the first signal and estimating a transmit gain adjustment value; code for transmitting a second signal using the transmit gain adjustment value; and code for receiving a reflection of the second signal and estimating the transmit gain adjustment value.

[0135] Clause 48. A method for controlling a receiver for radio frequency sensing in a wireless device, comprising: setting a receiving gain on the wireless device to a first level; transmitting a radio frequency signal using the wireless device at a first time, wherein the wireless device receives a leakage signal with a receiving gain at the first level; setting a receiving gain on the wireless device to a second level; receiving a reflection of the radio frequency signal using the wireless device at a second time, wherein the receiving gain is at the second level; and determining a distance to an object based at least in part on the difference between the first time and the second time.

[0136] Clause 49. An apparatus comprising: a memory; at least one transceiver including at least one transmit chain and at least one receive chain; at least one processor communicatively coupled to the memory and at least one transceiver, and configured to: set a receive gain on a wireless device to a first level; transmit a radio frequency signal using the wireless device at a first time, wherein the wireless device receives a leaked signal at the first level of receive gain; set a receive gain on the wireless device to a second level; receive a reflection of the radio frequency signal using the wireless device at a second time, wherein the receive gain is at the second level; and determine a distance to an object based at least in part on the difference between the first time and the second time.

[0137] Clause 50. An apparatus for controlling a receiver for radio frequency sensing in a wireless device, comprising: means for setting a receive gain on the wireless device to a first level; means for transmitting a radio frequency signal using the wireless device at a first time, wherein the wireless device receives a leakage signal at the first level of receive gain; means for setting a receive gain on the wireless device to a second level; means for receiving a reflection of the radio frequency signal using the wireless device at a second time, wherein the receive gain is at the second level; and means for determining a distance to an object based at least in part on the difference between the first time and the second time.

[0138] Clause 51. A non-transitory processor-readable storage medium comprising processor-readable instructions to cause one or more processors to control a receiver for radio frequency sensing in a wireless device, the non-transitory processor-readable storage medium comprising: code for setting a receive gain on the wireless device to a first level; code for transmitting a radio frequency signal using the wireless device at a first time, wherein the wireless device receives a leaked signal at the first level of receive gain; code for setting a receive gain on the wireless device to a second level; code for receiving a reflection of the radio frequency signal using the wireless device at a second time, wherein the receive gain is at the second level; and code for determining a distance to an object based at least in part on the difference between the first time and the second time.

Claims

1. A method for determining the distance to an object using radio frequency sensing, comprising: A radio frequency signal is transmitted using a transmission channel on a wireless device, wherein the radio frequency signal is a pre-specified sequence transmitted n times; The leaked signal is received on the wireless device using a receiving channel at the first moment, wherein the leaked signal is based on the radio frequency signal; At a second time, the wireless device receives a reflected signal using the receiving channel, wherein the reflected signal is based on the radio frequency signal reflected from the object, the reflected signal is at least one pre-specified sequence, where n is greater than 1, and wherein the reflected signal is m received sequences, where m is equal to or less than n; Combining the m received sequences to improve the signal-to-noise ratio (SNR) of the reflected signal; and The distance to the object is determined at least in part based on the difference between the first time and the second time.

2. The method according to claim 1, wherein, The pre-specified sequence is a single-carrier Zadoff-Chu sequence.

3. The method according to claim 1, wherein, The pre-specified sequence includes orthogonal frequency division multiplexing symbols.

4. The method according to claim 1, wherein, The pre-specified sequence includes one or more Wi-Fi packets.

5. The method of claim 1, further comprising transmitting a plurality of radio frequency signals and receiving one or more of the plurality of radio frequency signals.

6. The method of claim 1, further comprising transmitting multiple radio frequency signals using multiple transmission channels.

7. The method according to claim 1, wherein, Receiving the radio frequency signal includes receiving the radio frequency signal using multiple receiving links.

8. The method of claim 7, further comprising determining the angle of arrival of the received radio frequency signal.

9. The method of claim 1, further comprising determining the departure angle of the radio frequency signal.

10. The method of claim 1, wherein transmitting the radio frequency signal and receiving the radio frequency signal are performed using a single-chain transmit and receive operation.

11. An apparatus for determining the distance to an object using radio frequency sensing, comprising: At least one memory, the memory including instructions; At least one transceiver, including at least one transmit chain and at least one receive chain; At least one processor is configured to execute the instructions to cause the device to: Radio frequency signals are transmitted using the at least one transmission chain, wherein the radio frequency signals are a pre-specified sequence transmitted n times; The leaked signal is received using the at least one receiving link at the first moment, wherein the leaked signal is based on the radio frequency signal; In a second time, the at least one receiving link is used to receive reflected signals, wherein the reflected signals are based on the radio frequency signals reflected from the object, the reflected signals are at least one pre-specified sequence, where n is greater than 1, and wherein the reflected signals are m received sequences, where m is equal to or less than n; Combining the m received sequences to improve the signal-to-noise ratio (SNR) of the reflected signal; and The distance to the object is determined at least in part based on the difference between the first time and the second time.

12. The apparatus according to claim 11, wherein, The pre-specified sequence is a single-carrier Zadoff-Chu sequence.

13. The apparatus according to claim 11, wherein, The pre-specified sequence includes orthogonal frequency division multiplexing symbols.

14. The apparatus according to claim 11, wherein, The pre-specified sequence includes one or more Wi-Fi packets.

15. The apparatus according to claim 11, wherein, The at least one processor is further configured to cause the device to transmit a plurality of radio frequency signals and receive one or more of the plurality of radio frequency signals.

16. The apparatus according to claim 11, wherein, The at least one processor is further configured to enable the device to transmit multiple radio frequency signals using multiple transmission chains.

17. The apparatus according to claim 11, wherein, The at least one processor is further configured to enable the device to receive the radio frequency signal using multiple receiving links.

18. The apparatus according to claim 17, wherein, The at least one processor is further configured to enable the device to determine the angle of arrival of the received radio frequency signal.

19. The apparatus according to claim 11, wherein, The at least one processor is further configured to enable the device to determine the departure angle of the radio frequency signal.

20. The apparatus according to claim 11, wherein, The at least one processor is configured to enable the device to transmit and receive the radio frequency signal using a single-chain transmit and receive operation.

21. An apparatus for determining the distance to an object using radio frequency sensing, comprising: A component for transmitting radio frequency signals on a wireless device using a transmission channel, wherein the radio frequency signals are a pre-specified sequence transmitted n times; A component for receiving a leaked signal on the wireless device using a receiving channel at a first time, wherein the leaked signal is based on the radio frequency signal; Components for receiving reflected signals on the wireless device using the receiving channel at a second time, wherein the reflected signals are based on radio frequency signals reflected from the object, the reflected signals are at least one pre-specified sequence, where n is greater than 1, and wherein the reflected signals are m received sequences, where m is equal to or less than n; Components for combining the m received sequences to improve the signal-to-noise ratio (SNR) of the reflected signal; and A component for determining the distance to the object based at least in part on the difference between the first time and the second time.

22. The apparatus according to claim 21, wherein, The pre-specified sequence is a single-carrier Zadoff-Chu sequence.

23. The apparatus according to claim 21, wherein, The pre-specified sequence includes orthogonal frequency division multiplexing symbols.

24. The apparatus according to claim 21, wherein, The pre-specified sequence includes one or more Wi-Fi packets.

25. A non-transitory processor-readable storage medium comprising processor-readable instructions to cause one or more processors to determine a distance to an object using radio frequency sensing, the non-transitory processor-readable storage medium comprising: Code for transmitting radio frequency signals on a wireless device using a transmission channel, wherein the radio frequency signals are a pre-specified sequence transmitted n times; Code for receiving a leaked signal on the wireless device using a receiving channel at the first moment, wherein the leaked signal is based on the radio frequency signal; Code for receiving reflected signals on the wireless device using the receiving channel at a second time, wherein the reflected signals are based on the radio frequency signals reflected from the object, the reflected signals are at least one pre-specified sequence, where n is greater than 1, and wherein the reflected signals are m received sequences, where m is equal to or less than n; Code for combining the m received sequences to improve the signal-to-noise ratio (SNR) of the reflected signal; and Code for determining the distance to the object based at least in part on the difference between the first time and the second time.

26. The non-transitory processor-readable storage medium of claim 25, further comprising code for transmitting multiple radio frequency signals using multiple transmission channels.

27. The non-transitory processor-readable storage medium of claim 25, wherein the code for receiving the radio frequency signal includes code for receiving the radio frequency signal using a plurality of receiving links.

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