Our Christmas card for 2021 shows our WiFi Channel State Information (CSI) analysis while the song “Jingle Bells” was being played with a trumpet.
The CSI is available in the received packet preamble of the OFDM (Orthogonal Frequency Division Multiplexing) based WiFi standards such as IEEE 802.11a/n/ac/ax. Typically, the receiver uses it for channel equalization to recover data and then discards it. But the WiFi CSI is very sensitive to the changes in wireless environment and by processing it over time, it is possible to use the WiFi chip as a sensor. This technology is called WiFi Sensing and its typical applications areas are human presence detection, gesture recognition, intrusion detection and contactless vital signal (breathing and heart rate) monitoring. These applications can be implemented on consumer devices and run parallelly with existing connections, without limiting the data transfer.
You can read the exact specifications for the Christmas card here.
More information about CSI sensing can be found in our publication “In-Vehicle Breathing Rate Monitoring Based on WiFi Signals” from the European Microwave Week (EuMW2020).
