A Fully Integrated NB-IoT Wake-Up Receiver Utilizing An Optimized OFDM 12-Point FFT Wake-Up Engine

This work presents a fully integrated 28nm wake-up radio (WRX) for the NB-IoT protocol that includes a novel low-power OFDM digital baseband wake-up detector in addition to a low-noise RF front-end. This co-optimized WRX achieves the highest degree of integration for an NB-IoT WRX and is the only NB-IoT WRX to receive and process protocol standard OFDM signals on-chip. The digital baseband utilizes a 12-point FFT engine optimized for the NB-IoT Wake Up Signal (WUS), which reduces power consumption compared to a radix-2 implementation. This fully integrated WRX occupies an area of 2mm
²
and can be used stand-alone to wake up a main NB-IoT radio without the need to utilize an external digital modem or ADC. This WRX greatly reduces the power consumption of duty-cycled NB-IoT systems, increasing battery life without increasing latency.