Mesh Networking of CSI Sensor Nodes for Expanding Contactless Monitoring Coverage

This proof-of-concept study evaluates mesh networking protocols for extending Wi-Fi CSI vital sign monitoring coverage across multiple rooms in home environments. Three CSI sensing nodes (gateway, relay, remote) were deployed in a three-room residential setting and linked using a low-latency mesh protocol (IEEE 802.11s-inspired architecture). Packet relay via intermediate nodes improved sensing coverage from a single-room setup (∼35 m2) to three adjacent rooms (∼85 m2) while maintaining stable data continuity and <50 ms latency. Heart rate and respiration rate estimates from mesh-relayed CSI achieved 91.3 ± 4.2% accuracy relative to gateway-direct measurements, with negligible (< 2%) performance degradation. Network overhead: ∼8–12% packet retransmission rate across mesh links, with no packet loss over 30-day continuous operation. The paper highlights opportunities for non-clinical use cases such as elder care monitoring, workplace safety, and smart home wellness without requiring additional wearables or wall-mounted infrastructure. Key findings demonstrate that distributed CSI sensing via mesh networking is practical, reliable, and scalable for indoor multi-room environments.