# US 11,307,299 B2 · Radio frequency based sensing using communication signals

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- Number: US 11,307,299 B2
- Document ID: US11307299B2
- Status: Granted
- Kind: B2
- Application number: 16/534,106
- Filed: 2019-08-07
- Published: 2021-02-11
- Granted: 2022-04-19
- Earliest claimed: 2019-08-07
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Michael Kerner; Zohar Agon; Michael Ney
- Web page: https://patentgrep.com/patent/US11307299B2

## CPC

- G01S 13/34: using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
- H04L 25/0224: {using sounding signals}
- G01S 7/006: {using shared front-end circuitry, e.g. antennas (G01S13/765, G01S13/825 take precedence)}
- G01S 13/282: {using a frequency modulated carrier wave (G01S13/286 takes precedence)}
- G01S 13/343: {using sawtooth modulation}
- G01S 13/50: Systems of measurement based on relative movement of target
- H04L 25/0256: {Channel estimation using minimum mean square error criteria}
- H04L 27/2613: {Structure of the reference signals}
- H04W 64/006: {with additional information processing, e.g. for direction or speed determination}
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Embodiments are presented herein of apparatuses, systems, and methods for a wireless device to perform sensing applications using communication signals. The first wireless device may determine to perform a sensing application and to perform the sensing application using a communication signal to be transmitted to a second device. In other words, the first wireless device may use a transmission that is scheduled for communication purposes to additionally perform sensing of one or more types. Example sensing or radar-like applications include estimating distance, motion, and/or angle to one or more objects or structures in the vicinity of the first wireless device. After transmitting the communication signal to the second wireless device, the first wireless device may receive a reflection of the communication signal. The first wireless device may use the reflection to perform the sensing application.

## Claims

### Claim 1

An apparatus for managing a first wireless device, the apparatus comprising:
a processor configured to cause the first wireless device to:
determine to perform a measurement of distance to a reflector using one or more communication transmissions scheduled for transmission to a second wireless device, wherein the measurement of the distance to the reflector is concurrent with communication with the second wireless device;
transmit the one or more communication transmissions to the second wireless device;
receive at least one reflection of the one or more communication; transmissions;
perform, based on the at least one reflection, the measurement of the distance to the reflector; and
determine to perform a second measurement of the distance to the reflector using a frequency-modulated continuous-wave radar (FMCW) signal, wherein the determination to perform the second measurement of the distance to the reflector using the FMCW signal is based on a determination that an expected amount of communication is below a threshold.

### Claim 2 (depends on 1)

The apparatus of claim 1,
wherein the one or more communication transmissions include data and the at least one reflection of the one or more communication transmissions includes a reflection of the data, wherein the measurement of the distance to the reflector is performed based on the reflection of the data.

### Claim 3 (depends on 1)

The apparatus of claim 1, further configured to cause the first wireless device to receive, from the second wireless device, a response to at least one of the one or more communication transmissions, wherein the response is separate from the at least one reflection.

### Claim 4 (depends on 1)

The apparatus of claim 1,
wherein the one or more communication transmissions include a channel estimation sequence and the at least one reflection includes a reflection of the channel estimation sequence, wherein the measurement of the distance to the reflector is performed based on the reflection of the channel estimation sequence.

### Claim 5 (depends on 4)

The apparatus of claim 4,
wherein the one or more communication transmissions includes a wireless local area network transmission and the channel estimation sequence comprises one or more of:
a long training field (LTF); or
a channel estimation field (CEF).

### Claim 6

A first wireless device, comprising:
at least one antenna; and
a processor coupled to the at least one antenna and configured to cause the first wireless device to:
determine to perform a communication transmission to a second wireless device, wherein the communication transmission includes a plurality of data symbols;
determine to perform a first sensing measurement of a first reflector using a reflection of the communication transmission, wherein the first sensing measurement of the first reflector is based on a plurality of reflections corresponding to the plurality of data symbols;
transmit the communication transmission to the second wireless device;
receive, from the first reflector, the reflection of the communication transmission; and
perform the first sensing measurement of the first reflector using the reflection of the communication transmission, wherein at least one of a modified zero forcing estimator or a modified minimum mean square error estimator is used to perform a channel estimate of the plurality of reflections and the first sensing measurement of the first reflector is based on the channel estimate.

### Claim 7 (depends on 6)

The first wireless device of claim 6,
wherein the processor is further configured to cause the first wireless device to:
receive, from a second reflector, a second reflection of the communication transmission; and
perform a second sensing measurement of the second reflector using the second reflection of the communication transmission.

### Claim 8 (depends on 7)

The first wireless device of claim 7,
wherein the first sensing measurement and the second sensing measurement are ranging measurements, wherein the first sensing measurement includes a first time-of-flight estimate associated with the first reflector, and wherein the second sensing measurement includes a second time-of-flight estimate associated with the second reflector.

### Claim 9 (depends on 6)

The first wireless device of claim 6,
wherein the first sensing measurement includes an angle-of-arrival measurement.

### Claim 10 (depends on 6)

The first wireless device of claim 6,
wherein the first sensing measurement includes a measurement of speed or velocity.

### Claim 11 (depends on 6)

The first wireless device of claim 6,
wherein the processor is further configured to cause the first wireless device to:
receive, from the second wireless device, a response to the communication transmission; and
continue communication with the second wireless device based on the response.

### Claim 12

A method for performing a sensing measurement while performing communication, the method comprising:
at a first wireless device:
establishing communication with a second wireless device;
determining to perform a sensing measurement of a reflector while simultaneously communicating with the second wireless device, wherein said performing the sensing measurement of the reflector while simultaneously communicating with the second wireless device includes performing the sensing measurement without interrupting a data transfer with the second wireless device;
determining to perform the sensing measurement of the reflector using data symbols of the reflection of a packet, wherein said determining is based on a determination of availability of channel estimation sequences in scheduled transmissions;
transmitting, to the second wireless device, the packet;
receiving, from the reflector, a reflection of the packet; and
performing the sensing measurement based on the reflection of the packet.

### Claim 13 (depends on 12)

The method of claim 12,
wherein the packet includes payload data for the second wireless device, wherein the method further comprises receiving, from the second wireless device, a response to the packet.

### Claim 14 (depends on 12)

The method of claim 12, further comprising:
performing a channel estimate based on the reflection of the packet, wherein the sensing measurement is based on the channel estimate.

### Claim 15 (depends on 12)

The method of claim 12, wherein the determination of availability of channel estimation sequences in scheduled transmissions is based on a number of long training fields (LTFs).

### Claim 16 (depends on 12)

The method of claim 12, wherein the determination of availability of channel estimation sequences in scheduled transmissions is based on a number of channel estimation fields (CEFs).

### Claim 17 (depends on 12)

The method of claim 12, further comprising:
receiving, from the second wireless device, a response to the packet.

### Claim 18 (depends on 12)

The method of claim 12, further comprising:
receiving, from a second reflector, a second reflection of the packet; and
performing a second sensing measurement based on the second reflection of the packet.

### Claim 19 (depends on 12)

The method of claim 12, wherein the determination of availability of channel estimation sequences in scheduled transmissions is based on a number of reference signals associated with cellular communication.

### Claim 20 (depends on 12)

The method of claim 12, wherein the sensing measurement is performed based on one or more channel estimation sequences in addition to the data.