Challenges and directions of ultra low energy wireless sensor nodes for biosignal monitoring

This paper discusses design challenges and strategies for aggressively increasing energy efficiency of biosignal monitoring sensors. For the holistic understanding of energy efficiency, we introduce Energy Efficiency metric for all sensor communication blocks which include not only Rx/Tx RF&Analog, PLL and DSP/Modem but also Antenna and Power Management. Based on the metric, an ultra-low energy sensor node design at 2.36~2.5GHz is addressed from RFIC, DSP/Modem to Antenna. To tackle the stringent power requirements, we theoretically revisit the technology, circuits, architecture and system and explore the cross-layer power minimization algorithm.