Energy coverage in wireless powered sub-6 GHz and millimeter wave dense cellular networks

This paper focuses on the energy coverage in wireless powered sub-6 GHz and millimeter wave (mmWave) dense cellular networks, where mobile devices harvest RF energy from sub-6 GHz or mmWave base stations (BSs). The expressions for energy coverage probability in sub-6 GHz and mmWave tiers are respectively derived. The comparisons between sub-6 GHz and mmWave RF energy harvesting are analyzed. In particular, we provide the sufficient conditions for the case that wireless energy harvesting in mmWave tier is better than that in sub-6 GHz tier. Furthermore, in hybrid cellular networks with mode selection mechanism, the probability that a mobile device selects a sub-6 GHz BS or mmWave BS for wireless power transfer is also theoretically obtained.