Frequency-Division Multiplexed Wearable Wireless Sensor Network for Real-Time Motion Tracking using Magnetic Induction.

A new scheme is proposed for real-time multi-joint motion tracking using an on-body sensor network based on frequency-division multiplexed (FDM) magnetic induction (MI). The system employs wearable wireless sensor nodes that extract spatial information from measured node-to-node magnetic coupling. Unlike camera- or accelerometer-based motion-tracking approaches, the MI-based method does not require line of sight and does not accumulate errors due to sensor drift. A custom MI transceiver chip, fabricated in a standard bulk Complementary Metal Oxide Semiconductor (CMOS) process, drives a wearable coil and simultaneously measures tones transmitted by other nodes in full-duplex operation. The chip integrates a fully custom digital signal processor for real-time data analysis and supports a configurable capture rate of up to 977 frames per second. The system is experimentally validated using a 3D printed two-joint leg model and on-body demonstrations, and benchmarked against an open-source camera-based human pose estimation pipeline, demonstrating fully wireless, real-time MI-based motion tracking.