A 65-nm Sub-10-mW Communication/Ranging Quadrature Uncertain-IF IR-UWB Transceiver With Twin-OOK Modulation

This article describes a robust noncoherent transceiver architecture for pulse-based ultrawideband (UWB) communication systems. To address synchronization and interference issues in the conventional noncoherent transceiver with on–off keying (OOK) modulation, two techniques are proposed. The first one is twin-OOK (T-OOK) modulation, in which two pulses are used to represent 1-bit data. A short-duration synchronization pulse is employed for baseband synchronization, while a long-duration data pulse based on frequency-hopping (FH) OOK is employed for data transmission. The proposed modulation scheme not only addresses the synchronization problem of a transceiver baseband but also enhances the spectrum efficiency of a transmitter by adopting an FH method. The second one is uncertain-intermediate frequency (IF) down-conversion with quadrature demodulation. The quadrature uncertain-IF receiver achieves robust demodulation over frequency drift and good narrowband-interference (NBI) tolerance with an on-chip bandpass filter (BPF). In addition, ranging accuracy is enhanced with in-phase and quadrature (IQ) two-path signals. A prototype 6–8-GHz communication/ranging UWB transceiver is implemented in 65-nm CMOS. The transceiver achieves–71-dBm sensitivity at 10 Mb/s and 0.96-cm root-mean-square (rms) ranging accuracy. The transmitter and the receiver have the power consumption of 3.83 and 5.38 mW, respectively.