Making Wireless Body Area Networks Robust Under Cross-Technology Interference

Wireless body area networks (BANs) demand high-quality service. However, as BANs will be widely deployed in densely populated areas, they inevitably face RF cross-technology interference (CTI) from non-protocol-compliant wireless devices operating in the same spectrum range. The main challenges to defending against such a strong CTI come from the scarcity of spectrum resources, the uncertainty of the CTI sources and BAN channel status, and the stringent hardware constraints. In this paper, we first experimentally characterize the adverse effect on BAN reliability caused by the non-protocol-compliant CTI. Then, we formulate a joint routing and power control (JRPC) problem, which aims at minimizing energy consumption under strong CTI while satisfying node reachability and delay constraints. We reformulate our problem into a mixed integer linear programing problem and then derive the optimal results through IBM's CPLEX. A practical protocol, including a heuristic JRPC algorithm, is then proposed, in which we address the challenge of fast link-quality measurement by proposing a passive link-quality estimation and prediction method. Through experiments and simulations, we show that our protocol can assure the robustness of BAN even when the CTI sources are in very close vicinity, using a small amount of energy on commercial-off-the-shelf sensor devices.