A 0.77mW 1.84nJ/bit Phase Noise Canceling Receiver for QAM and OFDM and Cellular IoT

A low-power RX is presented for cellular IoT applications. The RX utilizes a phase noise cancelling architecture designed for QPSK/QAM and OFDM and consumes 612μW for QPSK and 765μW for 16QAM. The RX utilizes a mixer-first and self-mixing hybrid architecture and uses an optimized analog squarer to cancel the phase noise of the ring oscillator (RO) with the addition of a pilot tone. The RX can demodulate phase-modulated data despite the use of a high phase noise RO. Additionally, the RX can coherently demodulate QPSK/QAM data without the need for phase synchronization or a PLL. The RX achieves a high data rate at low power and has the lowest energy per bit for a <1mW RX at 1.84nJ/bit. The RX achieves a normalized sensitivity of -98/-93dBm for QPSK/16QAM and OFDM. The RX is the only low-power RX that can support QAM and OFDM.