Ambient radio frequency (RF) energy harvesting has emerged as a promising solution for powering small devices and sensors in massive Internet of Things (IoT) ecosystem due to its ubiquity and cost efficiency. In this presentation, a stochastic geometry-based analysis of the joint uplink and downlink coverage of cellular-based ambient RF energy harvesting IoT will be discussed. In the considered system, the cellular network is assumed to be the only source of RF energy. A time division-based approach is assumed for power and information transmission where each time slot is partitioned into three sub-slots: (i) charging sub-slot during which the cellular base stations (BSs) act as RF chargers for the IoT devices, which then use the energy harvested in this sub-slot for information transmission and/or reception during the following sub-slots, (ii) downlink sub-slot during which the IoT device receives information from the associated BS, and (iii) uplink sub-slot during which the IoT device transmits information to the associated BS. For this setup, the key technical challenges in deriving the joint uplink and downlink coverage probability are discussed. A journal version of the work described in the above presentation can be found at https://arxiv.org/abs/1705.06799.