Domino: Dominant Path-Based Compensation for Hardware Impairments in Modern WiFi Sensing

WiFi sensing faces a critical reliability challenge due to hardware-induced RF distortions, especially with modern, market-dominant WiFi cards supporting 802.11ac/ax protocols. These cards employ sensitive automatic gain control and separate RF chains, introducing complex and dynamic distortions that render existing compensation methods ineffective. In this paper, we introduce Domino, a new framework that transforms channel state information (CSI) into channel impulse response (CIR) and leverages it for precise distortion compensation. Domino is built on the key insight that hardware-induced distortions impact all signal paths uniformly, allowing the dominant static path to serve as a reliable reference for effective compensation through delay-domain processing. Real-world respiration monitoring experiments show that Domino achieves at least 2× higher mean accuracy over existing methods, maintaining robust performance with a median error below 0.24 bpm, even using a single antenna in both direct line-of-sight and obstructed scenarios.