An End-to-End Dual ASIC OFDM Transceiver for Ultrasound In-Body Communication

Area of Science:

• Biomedical Engineering
• Wireless Communication Systems
• Implantable Medical Devices

Background:

• Implanted medical devices require reliable, secure, and low-energy wireless communication.
• Ultrasound (US) offers advantages like low body attenuation and inherent security for in-body communication.
• Existing US communication systems often overlook realistic channel conditions or are not suitable for small, energy-constrained systems.

Purpose of the Study:

• To develop a custom, hardware-efficient Orthogonal Frequency Division Multiplexing (OFDM) modem for ultrasound in-body communication.
• To address the limitations of existing systems by optimizing for diverse channel conditions and energy scarcity.

Main Methods:

• Implementation of a dual Application-Specific Integrated Circuit (ASIC) transceiver: a 180 nm BCD analog front-end and a 65 nm CMOS digital baseband chip.
• Integration of tuning capabilities for analog dynamic range, OFDM parameters, and baseband processing to adapt to channel variability.

Main Results:

• Achieved 470 kbps data rate with a Bit Error Rate (BER) of 3e-4 in ex-vivo experiments.
• Demonstrated low power consumption: 56 nJ/bit for transmission (Tx) and 10.9 nJ/bit for reception (Rx).

Conclusions:

• The custom OFDM modem provides an efficient and adaptable solution for ultrasound in-body communication.
• The developed ASIC transceiver enables reliable, high-speed, and low-power wireless links for implantable medical devices.