An OFDMA Baseband Processor Enabling $165\mu \mathrm{W}$ Long-Range IoT Localization

We present an OFDMA baseband localization processor fabricated in 22nm, co-designed with a low-power, crystal-less narrowband RF receiver chip that efficiently estimates the channel frequency response in real-time for localization. The localization processor consumes 1.52/2.04mW for 2/3D localization processing, and duty-cycles the RF receiver achieving 247nW standby power. The combined system achieves a localization distance of 430m, a 4.3× improvement over state-of-the-art, while maintaining comparable accuracy. We deploy this system in a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\times 2.8$</tex> cm IoT localization tag with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$165\mu \mathrm{W}$</tex> average power at 0.1 Hz location acquisition rate.