Parallel Feedback Communications for Magnetic MIMO Wireless Power Transfer System

Receiver (RX) feedback and power transfer channel estimation are essential for enhancing the context-aware ability for magnetic resonant coupling (MRC) enabled wireless power transfer (WPT) systems. Solutions are not highly efficient and immature in MIMO scenarios. In this work, we investigate the concurrent feedback communications for multiple RXs equipped with oscillating circuits. We discover an interesting clustering phenomenon, where the TX currents form clusters in corresponding to the combined RX "Open-Short" states. Based on this, we propose a parallel multi-stage decoding scheme by identifying the combined state for each cluster. In symbol clustering stage, we introduce two-layer clustering mechanism to tackle the "dominant RXs" challenge which causes inaccurate classification results. In cluster identification stage, we solve the "ambiguous identification candidates" challenge by calibration based on power transfer channel condition estimation. We have implemented the prototype testbed using off-the-shelf components. Our experiment results demonstrate the effectiveness of the proposed scheme. Our system supports communication within valid charging area even under significant interference from other RX. The simulation results further suggest the scalability of the proposed scheme, and the accuracy for power transfer channel estimation.