Surviving the RF smog: Making Body Area Networks robust to cross-technology interference

Wireless Body Area Networks (BANs) demand for highly robust communication due to the criticality and time-sensitivity of the medical monitoring data. However, as BANs will be widely deployed in densely populated areas, they inevitably face the RF cross-technology interference (CTI) from non-protocol-compliant wireless devices operating in the same spectrum range, which are persistent, high power, and broadband in nature. The main challenges to defend such strong CTI come from the scarcity of spectrum resources, the uncertainty of the CTI sources and BAN channel status, and the stringent hardware constraints. Existing methods fail because of their need for extra spectrum resources or advanced hardware. In this paper, we first experimentally characterize the adverse effect on BAN reliability caused by the non-protocol-compliant CTI. Then we propose a CTI-aware joint routing and power control (JRPC) approach to ensure desired reliability goals using minimum energy resources even under strong co-channel CTI. To cope with channel uncertainty, we propose a passive link quality estimation method which exploits prediction. Through extensive experiments and simulations, we show that our proposed protocol can assure the robustness of BAN even when the CTI sources are in very close vicinity, using little overall energy and spectrum resources, and can be easily implemented on commercial-off-the-shelf (COTS) devices.