Are narrowband wireless on-body networks wide-sense stationary?

Using narrowband wireless On-Body Area Network (BAN) channel measurements (50 million data points) in diverse environments with multiple subjects, we examine the stationarity of the channel. Wide-Sense Stationarity (WSS) tests and power spectral estimates show that the channel has a 50% probability of stationarity at 500 ms and the probability rapidly diminishes thereafter. We show that non-stationarity is inherent to on-body BANs and not an artifact of experimental setup.