A 16-QAM-Based Multi-Node BCC System with Bias-Electrode-Free Multi-Channel ExG Readout ICs

We present a system for multi-node body channel communication (BCC) integrated with multi-channel ExG readout ICs. By utilizing time-multiplexing for BCC communication and ExG measurement, the system minimizes interference between the BCC signal and the ExG readout IC, enabling the measurement of EEG, which requires ultra-low noise, along with EOG, EMG, and ECG signals. Moreover, eliminating the bias electrode increases BCC signal amplitude by 60%, allowing 16-QAM communication at 8Mbps even under time-multiplexing operation. To guarantee the robustness of communication, the system adaptively switches to OOK modulation in cases of significant body channel loss. Additionally, the system employs a multi-channel least-mean-square (LMS) filter and a DC servo loop (DSL) to effectively address channel mismatches and differential artifacts.