A QPSK/16-QAM OFDM-based 29.1Mbps LINC Transmitter for Body Channel Communication

Abstract

This paper proposed a high speed Body Channel Communication (BCC) transmitter under IF 20MHz, adopting the OFDM modulation and uneven multi-level LINC technique to reduce the power and complexity of the front-end circuit. The OFDM uses 16-QAM modulation to enhance the data rate and could select to use a convolutional code to increase the coding gain. The phase modulator in the LInear amplification with Nonlinear Component (LINC) transmitter uses not only clock-gating scheme but also the glitch free protection. A detection and calibration DSP are also integrated to solve the LINC branch mismatch problem. Finally the capacitive sensing circuit provides the information of the connectivity between pastes and human. The chip is implemented by 90nm CMOS process, with die area 1.3mm(2). The maximum data rate could achieve 29.1Mbps. The total power is 1.925mW, resulting in 0.07nJ/bit transmission energy and 2.92 bps/Hz spectral efficiency.