Superregenerative Wake-Up Receiver with 20 µW Power Consumption for Human Body Communications

The previous research works have shown that the modulation of the electric field induced on the human body surface enables to transfer data wirelessly. Method is known as human body communications (HBC) which has multiple advantages in comparison to traditional wireless radio communications over air. They include lower attenuation, less interference to/from other wireless devices, as well as the better security due to higher resistance against eavesdropping. In this paper we propose a wake-up receiver (WUR) which improves energy efficiency in the HBC-based wireless body area networks (WBAN) taking into account the latency requirements. The WUR continuously scans the HBC channel looking for the specified wake-up signal whilst consuming very low amount of energy. Once receiving the wake-up signal, the receiver awakes the main controller and the data radio of the WBAN node from sleep mode. In this paper, we first propose the design of the low-power WUR based on the superregenerative principle and then present the performance results measured from an implemented prototype. The measurements show that the designed WUR achieves a sensitivity of -63.8 dBm with the bit error rate (BER) of 10-3, whilst consuming only 20 μW in average while waiting for a wake-up signal, and 23 μW whilst receiving the signal.