An Energy Efficient Multi-User Asynchronous Wireless Transmitter for Biomedical Signal Acquisition.

Area of Science:

• Biomedical Engineering
• Wireless Communication Systems
• Signal Processing

Background:

• Simultaneous multi-user wireless acquisition of biological signals is crucial for advanced healthcare monitoring.
• Existing systems often face challenges with energy efficiency and size reduction, particularly in implantable or wearable devices.
• There is a need for robust, low-power transmitter architectures capable of handling asynchronous data streams from multiple biosensors.

Purpose of the Study:

• To present a novel transmitter architecture for short-range asynchronous wireless communication.
• To enable simultaneous multi-user wireless acquisition of biological signals using a Time-Encoding Machine.
• To demonstrate an energy-efficient and size-reduced solution for biomedical applications.

Main Methods:

• Utilized an Integral Pulse Frequency Modulator (IPFM) as a Time-Encoding Machine to convert analog biosensor signals into time information.
• Implemented a microprocessor-free multi-user coding scheme based on unique feedback loop delays in each transmitter.
• Integrated IPFM pulses with an Impulse Radio Ultra-Wideband (IR-UWB) pulse generator for signal transmission.
• Fabricated the Time-Encoded UWB (TE-UWB) transmitter using 0.18 μm CMOS technology.

Main Results:

• The IPFM demonstrated a linear relationship between output pulse distance and analog input voltage (0.15 V to 1.5 V).
• The TE-UWB transmitter achieved low power consumption, ranging from 10.8 μW to 40.48 μW.
• The implemented circuit occupied a small area of 0.14 mm².
• Successful multi-user coding was achieved without an internal clock or microprocessor, enhancing energy efficiency.

Conclusions:

• The proposed TE-UWB transmitter architecture is highly suitable for simultaneous multi-user wireless acquisition of biological signals.
• The design meets critical demands for energy efficiency and size reduction in biomedical applications.
• The IPFM-based time-encoding approach offers a viable solution for low-power, asynchronous wireless communication.