A Pseudo OFDM With Miniaturized FSK Demodulation Body-Coupled Communication Transceiver for Binaural Hearing Aids in 65 nm CMOS

A power-efficient body-coupled communication pseudo orthogonal frequency-division multiplexing (P-OFDM) transceiver (TRX) is presented for binaural hearing aids (BHAs). Channel measurements are performed for different body postures between human head-to-hand and ear-to-ear to characterize the body channel path loss. The TRX exploits baseband 16-quadrature amplitude modulation OFDM symbols transmitted through a binary frequency-shift keying (FSK) modulation to mitigate the multipath and interference problems, which are the most serious issues in BHA, with bit error rate improvement of 74% compared to FSK. It is also free from the peak-to-average power ratio problem. A power-of-two decomposition constant multiplier is implemented to achieve area-efficient constant multiplications in 64-FFT. The proposed energyand area-efficient miniaturized direct conversion FSK demodulation receiver is capable of demodulating up to 20 Mbps signals while reducing the area by >50% compared to conventional implementations. The 1 Mbps TRX is implemented in a 65 nm CMOS process with an active area of 2.13 mm2while consuming 1.4 mW.