A GMSK/PAM4 Multichannel Magnetic Human Body Communication Transceiver

This letter presents a dual-mode multichannel transceiver implemented with low path loss offered by magnetic human body communication (mHBC) toward ultraefficient body-area networking. Two spectral-efficient modulation schemes: 1) Gaussian minimum-shift keying (GMSK) and 2) 4-level pulse-amplitude modulation (PAM4), are used to reduce interference on adjacent channels. A power oscillator is used to efficiently generate both GMSK- and PAM4-modulated magnetic fields while multichannel selection is implemented by on-chip capacitor tuning and an analog PLL, enabling 5 and 10 Mb/s data for GMSK and PAM4, respectively. The transmitter achieves an efficiency of 15.5 and 19.4 pJ/bit, while the receiver consumes 4.6 and 2.7 pJ/bit for GMSK and PAM4, respectively.