Entropy-Maximization Based Adaptive Frequency Hopping For Wireless Medical Telemetry Systems

In this paper, we propose an adaptive frequency hopping algorithm, entitled robust adaptive frequency hopping (RAFH), for increased reliability of wireless medical telemetry system (WMTS) under coexistence environment with non-medical devices. The conventional adaptive frequency hopping (AFH) scheme classifies channels into "good" or "bad" according to the threshold-based on-off decision, and uses good channels with a uniform hop probability. Unlike the conventional AFH scheme, RAFH solves a constrained entropy maximization problem and assigns each channel a different hop probability, which is a decreasing function of the measured PER. By adopting constrained entropy maximization, RAFH not only improves the average PER, but also reduces the PER fluctuation under dynamic interference environment. Our simulation studies show that RAFH outperforms the basic FH and the conventional AFH with respect to the PER under various scenarios of dynamic interference.