A novel low-power compact WBS human body channel receiver for wearable vital signal sensing application in wireless body-area network

This paper presents a low-power compact wideband signaling (WBS) human body channel (HBC) receiver for wearable vital sensing application in wireless body-area network. By investigating the characterization of HBC in frequency-domain and time-domain, a simply empirical HBC channel model over 1–100 MHz is proposed, and represented as a bandpass filter with its output signals of weak narrow pulses in 30 ns-width. According to the measurement and modeling for HBC, the proposed WBS based HBC receiver exploits an architecture with a low-power compact two-stage analog front end (AFE) followed by an all-digital data recovery circuit. To further reduce the power consumption and chip area, the AFE incorporates a capacitor-coupling pre-amplifier and a fully adjustable process, voltage, temperature independent 1-bit digitizer based on Schmitt trigger. Furthermore, the all-digital data recovery circuit adopts the feedforward 3-phase oversampling algorithm for low-jitter output with approximate 50% duty-cycle. With implementation in SMIC 130 nm CMOS technology, the proposed WBS based HBC receiver achieves 5 Mb/s operation with the power dissipation of 0.82 mW at a 1.2 V supply voltage while occupying a chip area of 0.26 mm².