  Fog computing can be used to offload computationally intensive tasks from
battery powered Internet of Things (IoT) devices. Although it reduces energy
required for computations in an IoT device, it uses energy for communications
with the fog. This paper analyzes when usage of fog computing is more energy
efficient than local computing. Detailed energy consumption models are built in
both scenarios with the focus set on the relation between energy consumption
and distortion introduced by a Power Amplifier (PA). Numerical results show
that task offloading to a fog is the most energy efficient for short, wideband
links.
