Signal Preemphasis Technique for 10–60 MHz High-Speed Implant Communication System With Bandwidth-Limited Small Antennas

摘要

Real-time and high-quality control of implant robots requires wireless communication with tens of Mb/s high data rate and communication distance deeper than ten centimeters within the human body. However, the frequency-dependent human tissue properties and the small implant antenna’s narrow bandwidth can lead to severe channel distortion and bandwidth limitations, restricting the transmission speed and distance significantly. This study aims to achieve a high data rate of 20 Mb/s for an implant communication system equipped with narrow-band small antennas, within the 10–60 MHz human body communication (HBC) band. A signal pre-emphasis technique is proposed to mitigate channel distortion and overcome bandwidth limitations by pre-compensating the channel response while shaping the waveform of the transmitted signal. By the proposed pre-emphasis technique, numerical simulation with an anatomical human body model shows that the receiving bandwidth is increased from 9.0 MHz to 46.5 MHz, while reliable communication distance is achieved to 8 cm within the body model. Moreover, experimental measurement with a tissue-equivalent liquid phantom shows that the same antenna as in the simulation realizes a communication distance of 6 cm, while a better-designed wideband antenna enhances the distance to 10 cm.