A Context-aware Reconfigurable Transmitter with 2.24 pJ/bit, 802.15.6 NB-HBC and 4.93 pJ/bit, 400.9 MHz MedRadio Modes with 33.6% Transmit Efficiency

The emerging Narrowband Human Body Communication (NB-HBC) technology, as well as MedRadio communication in the 400 MHz band promise better energy efficiencies than traditional Bluetooth Low Energy for wireless body area networks (WBAN) due to lower channel losses and lower frequencies, respectively. Although HBC offers less than 10pJ/bit energy efficiencies, it strictly demands both the transmitter and receiver to be on the body. Traditional MedRadio enables data transfer even when either devices are not on the body, but consumes orders of magnitude more energy than HBC, primarily due to large power consumption in LO generation. In this work, for the first time, we demonstrate a COntext-aware, Reconfigurable transmitter (COR-Tx) consisting sub-3pJ/bit HBC and sub-5pJ/bit MedRadio modes (both state-of-the-art), while supporting opportunistic switching between the two modes depending on the location of the receiver (on-body/off-body) for achieving optimum system-level energy with seamless communication. For 10 Mbps data rate, the HBC mode achieves an energy efficiency of 2.24pJ/bit, while the MedRadio mode achieves 4.93pJ/bit using a shared LO generation scheme that utilizes direct-modulated edge combination (EC) for minimizing energy consumption. The energy-efficiency improvement over the state-of-the-art is ~2.1X for HBC and ~90X for MedRadio.