Channel Characteristics of Dynamic Off-Body Communications at 60 GHz Under Line-of-Sight (LOS) and Non-LOS Conditions

This letter investigates the first-order characteristics of dynamic off-body communications channels at 60 GHz. In particular, we have studied signal propagation from a chest-worn millimeter-wave transmitter as an adult male walked toward and then away from a hypothetical base station. The mobile line-of-sight (LOS) and non-LOS (NLOS) channel measurements have been conducted in a diverse range of environments, including a hallway, an open office, an anechoic chamber, and an outdoor car park. In this study, we have decomposed the received signal into its path loss, large-scale, and small-scale fading components. The large-scale fading has been modeled using the gamma distribution, while the Rice and Nakagami-$m$ distributions have been employed to describe the small-scale fading observed in the LOS and NLOS channel conditions, respectively. The results have shown that the estimated path loss exponents for the anechoic chamber and car park environments were greater than those obtained for the hallway and open office environments for both the LOS and NLOS walking scenarios. Across all environments, it was found that the gamma distribution provided an adequate fit to the large-scale fading. Additionally, the Rice and Nakagami-$m$ distributions were found to well describe the small-scale fading for the LOS and NLOS walking scenarios, respectively.