Method, apparatus, and system for wireless vital monitoring using high frequency signals

Patent metadata

Field	Value
Publication number	US-12004838-B2
Application number	US-202217945995-A
Country	US
Kind code	B2
Filing date	Sep 15, 2022
Priority date	Feb 13, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

Methods, apparatus and systems for wireless vital sign monitoring are described. In one example, a described system comprises: a transmitter configured to transmit a wireless signal through a wireless channel of a venue; a receiver configured to receive the wireless signal through the wireless channel that is being impacted by an object motion of an object in the venue; and a processor. At least one of the transmitter or the receiver comprises an array of antennas used to transmit or receive the wireless signal. The object motion comprises at least one non-periodic body motion of the object and at least one periodic vital-sign motion of the object. The processor is configured for: segmenting space around the venue into a plurality of sectors based on a beamforming and the received wireless signal, wherein each sector of the plurality of sectors is associated with a spatial direction relative to the array of antennas, obtaining a plurality of time series of channel information (CI) of the wireless channel based on the beamforming, wherein each time series of CI (TSCI) of the plurality of TSCI is associated with a respective sector of the plurality of sectors, isolating the object motion of the object in the plurality of TSCI to generate a plurality of isolated TSCI, compensating for the at least one non-periodic body motion of the object in the plurality of isolated TSCI to generate a plurality of compensated TSCI, and monitoring the at least one periodic vital-sign motion of the object based on the plurality of compensated TSCI.

First claim

We claim:

1. A system for vital sign monitoring based on wireless beamforming, comprising:
a transmitter configured to transmit a wireless signal through a wireless channel of a venue;
a receiver configured to receive the wireless signal through the wireless channel that is being impacted by an object motion of an object in the venue, wherein
at least one of the transmitter or the receiver comprises an array of antennas used to transmit or receive the wireless signal,
the object motion comprises at least one non-periodic body motion of the object and at least one periodic vital-sign motion of the object; and

a processor configured for:
segmenting space around the venue into a plurality of sectors based on a beamforming and the received wireless signal, wherein each sector of the plurality of sectors is associated with a spatial direction relative to the array of antennas,
obtaining a plurality of time series of channel information (CI) of the wireless channel based on the beamforming, wherein each time series of CI (TSCI) of the plurality of TSCI is associated with a respective sector of the plurality of sectors,
isolating the object motion of the object in the plurality of TSCI to generate a plurality of isolated TSCI,
compensating for the at least one non-periodic body motion of the object in the plurality of isolated TSCI to generate a plurality of compensated TSCI, wherein the compensating comprises:
determining a first CI of a first TSCI in the plurality of isolated TSCI,
determining a second CI and a third CI of a second TSCI in the plurality of isolated TSCI, wherein the first CI and the second CI are associated with a common time stamp, wherein the third CI is temporally adjacent to the common time stamp,
computing a cross correlation function between a temporal profile of the first CI and a temporal profile of the third CI,
computing a maximum point of the cross correlation function,
computing a best shifting amount for the temporal profile of the first CI with respect to the third CI based on the maximum point of the cross correlation function,
computing a shifted first CI by shifting the temporal profile of the first CI based on the best shifting amount, and
replacing the second CI with the shifted first CI, and

monitoring the at least one periodic vital-sign motion of the object based on the plurality of compensated TSCI.

2. The system of claim 1 , wherein isolating the object motion of the object comprises:
filtering each TSCI of the plurality of TSCI based on a filter to isolate the object motion of the object in the TSCI.

3. The system of claim 2 , wherein the filter is one of: a moving-average (MA) filter, an autoregressive (AR) filter, or an autoregressive-moving-average (ARMA) filter.

4. The system of claim 3 , wherein filtering each TSCI comprises:
subtracting a weighted average of a number of past CI from a current CI in the TSCI to generate a filtered CI.

5. The system of claim 1 , wherein
a first non-periodic body motion of the object is larger than a range-azimuth resolution.

6. The system of claim 1 , wherein compensating for the at least one non-periodic body motion of the object further comprises:
determining the third CI of the second TSCI as a reference CI;
for each respective TSCI of the plurality of isolated TSCI:
determining a respective candidate first CI of the respective TSCI, wherein the second CI and the candidate first CI are associated with the common time stamp,
computing a respective cross correlation function between a temporal profile of the reference CI and a temporal profile of a respective candidate first CI of the respective TSCI, and
computing a respective maximum point of the respective cross correlation function;

computing a dominant maximum point among all of the maximum points;
determining the isolated TSCI associated with the dominant maximum point as the first TSCI;
determining the respective candidate first CI associated with the dominant maximum point as the first CI; and
computing the best shifting amount for the temporal profile of the first CI based on a time shift associated with the dominant maximum point.

7. The system of claim 1 , wherein:
the first TSCI and the second TSCI are a common TSCI;
the first CI is the second CI;
each CI comprises a temporal profile;
shifting the first CI comprises shifting the temporal profile of the first CI; and
compensating for the at least one non-periodic body motion of the object further comprises:
computing a cross correlation function between the temporal profile of the first CI and the temporal profile of a third CI of the common TSCI, wherein the third CI is temporally adjacent to the first CI,
computing a maximum point of the cross correlation function,
shifting the temporal profile of the first CI by an amount equal to a time shift associated with the maximum point, and
replacing the first CI of the first TSCI by the shifted first CI.

8. The system of claim 1 , wherein:
the first CI is shifted using one of: circular shifting or non-circular shifting; and
compensating for the at least one non-periodic body motion of the object comprises:
for each respective TSCI of the plurality of TSCI, computing a magnitude feature of a weighted average of a respective CI of the respective TSCI in a time window, and
for each respective TSCI of the plurality of TSCI, associating the respective TSCI and a respective associated sector with the object when the magnitude feature is greater than a threshold.

9. The system of claim 8 , wherein compensating for the at least one non-periodic body motion of the object further comprises:
computing at least one time series of CI feature (CIF), wherein
each respective time series of CIF (TSCIF) of the at least one TSCIF is associated with a corresponding TSCI associated with the object,
each CIF of the respective TSCIF is a feature of a respective CI of the corresponding TSCI;

computing an estimate of a second non-periodic body motion of the object based on a smoothing spline, wherein the second non-periodic body motion is smaller than the range-azimuth resolution; and
subtracting the estimate from the at least one TSCIF to compensate for the second non-periodic body motion of the object.

10. The system of claim 8 , wherein the feature of the respective CI comprises at least one of: a phase, a magnitude, a function of phase, a function of magnitude, or a function of phase and magnitude, of the respective CI.

11. The system of claim 10 , wherein monitoring the at least one periodic vital-sign motion of the object comprises:
classifying a particular sector among the plurality of sectors as a vital-sign sector based on the at least one TSCIF, wherein the vital-sign sector is associated with the at least one periodic vital-sign motion of the object.

12. The system of claim 11 , wherein classifying the sector comprises:
computing at least one autocorrelation function (ACF) based on the at least one TSCIF, each ACF being an ACF of a respective TSCIF associated with a respective TSCI of a respective sector;
computing at least one feature point of the at least one ACF, each feature point being of a respective ACF associated with a respective sector; and
classifying the particular sector associated with a particular feature point as the vital-sign sector when the particular feature point exceeds a threshold.

13. The system of claim 12 , wherein the feature point comprises at least one of:
a maximum point, a magnitude of a maximum point, a timing associated with a maximum point,
a minimum point, a magnitude of a minimum point, a timing associated with a mi

Assignees

• Wang Fengyu
• Wang Beibei
• Zeng Xiaolu
• Wu Chenshu
• Liu K J Ray
• Au Oscar Chi Lim
• Origin Res Wireless Inc

Inventors

• Wang Fengyu
• Wang Beibei
• Zeng Xiaolu
• Wu Chenshu
• Liu K J Ray
• Au Oscar Chi-Lim

Classifications

• G01S13/88

  Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) · CPC title

• A61B5/7207

  of noise induced by motion artifacts · CPC title

• A61B5/0507

  using microwaves or terahertz waves · CPC title

• A61B5/02405

  Determining heart rate variability · CPC title

• A61B5/0026

  characterised by the transmission medium · CPC title