Concurrent monitoring of indoor oxygen concentration levels and human vital signs with mmWave radar sensors

A method of operating a device, the method comprising:

• sending, by a frequency-modulated continuous wave (FMCW) radar that operates in a millimeter wave (mmWave) frequency range, a first signal having a sequence of chirps comprising a first chirp that is a triangular-type chirp that increases in frequency for a first period and decreases in the frequency for a second period and a second chirp that is a ramp-type chirp that increases in the frequency for a third period;
• receiving, by the FMCW radar, a second signal corresponding to the first signal, the second signal comprising a first portion corresponding to the first chirp and a second portion corresponding to the second chirp;
• generating, by a processing device and using the first chirp and the first portion, a third signal indicative of a human vital sign, wherein the human vital sign is a heart rate or a respiratory rate;
• measuring, by the processing device, a received signal strength indicator (RSSI) value of the second portion at the frequency in a range of 55-65 GHz;
• and
• determining, by the processing device and using the RSSI value, a value indicative of oxygen-concentration in an ambient environment of the device.

A method of operating a device with a frequency-modulated continuous wave (FMCW) radar that operates in a millimeter wave (mmWave) frequency range, the method comprising:

• sending a first signal having a sequence of chirps comprising a first chirp that is a triangular-type chirp that increases in frequency for a first period and decreases in the frequency for a second period and a second chirp that is a ramp-type chirp that increases in the frequency for a third period;
• receiving a second signal corresponding to the first signal, the second signal comprising a first portion corresponding to the first chirp and a second portion corresponding to the second chirp;
• generating, using the first chirp and the first portion, a third signal indicative of a human vital sign, wherein the human vital sign is a heart rate or a respiratory rate;
• measuring a received signal strength indicator (RSSI) value of the second portion at the frequency in a range of 55-65 GHz;
• and
• determining, using the RSSI value, a value indicative of oxygen-concentration in an ambient environment of the device.