Clock offset tracking for subsampling UWB architectures in a body area network

Ultra-wideband (UWB) impulse radio is a promising technique for low-power body area communication systems. While a range of analog and digital UWB transceiver architectures exist, a mostly-digital approach without analog downconversion would enable better technology scaling and signal processing flexibility. Furthermore, recently proposed subsampling schemes and advances in high-speed ADC circuit design now make this approach feasible at low power. However, subsampling systems require the extra overhead of a Hilbert transform to generate the in-phase and quadrature components necessary for phase estimation and tracking in coherent receivers. This can potentially lead to higher power consumption. To address this problem, we present several low-complexity Hilbert transform solutions suitable for UWB systems. In addition, we propose a clock frequency offset tracking mechanism and develop an analytical model of its performance. Finally, we use this model to analyze our proposal in a body area communication channel. This paper presents and evaluates a complete subsampling clock frequency tracking implementation targeting body area communication.