SOLI: A Tiny Device for a New Human Machine Interface

Abstract

With the introduction of the Internet of Things (IoT), there is an increasing focus on human-to-machine interaction. Nowadays, sensors make system and robots to see, hear, feel, and intuitively “understand” their surroundings. 60GHz radar [1] provides a very attractive solution for the sensing of human motion, enabling specific use cases such as: smart presence, hand gesture, and vital signs monitoring. Those can enhance the user experience in wearables, mobile devices, TVs, smart homes, automotive infotainment systems and AR-VR applications. The high bandwidth allocated in the 60GHz band (from 57 to 64GHz) enables very high range resolution sensing ($\approx$ 2cm), which, when complemented with micro-Doppler and time domain analysis [2], offers a powerful tool for discriminating complex hand movements with millimeter accuracy. The solution presented in this paper represents the a tiny radar system integrated into a smartphone, the Google Pixel 4. The simplified signal flow pipeline, from the radar sensor up to the signal transformation and classification, is presented in Fig. 2.3.1 [3]. The radar sensor is designed primarily taking into account all the integration boundaries, which includes in primis power consumption and package size (including antenna). Specifically, the power consumption requirement translates to a very stringent requirement for the maximum number of chirps the sensor could run per frame, impacting the process gain, and so the maximum detection range.