Energy Optimization in Association-Free Fog-IoT Networks

Minimizing energy consumption while providing quality of service (QoS) is of paramount importance for energy-constrained networks, such as Internet of Things (IoT). The emergence of fog computing in IoT has the great potential to reduce the energy consumption of IoT nodes, which also known as terminal nodes (TNs), and also minimizing the task delays. However, this in general comes at the price of the higher energy consumption of fog nodes (FNs). This paper aims to study the energy consumption tradeoff between TNs and FNs in the Fog-IoT system. To this end, we first propose a new protocol, where TNs immediately broadcast their data with the certain transmission rate to potentially all FNs without the need of prior determination which FN to associate with. Upon receiving the requests, FNs determine whether to process the requests locally or forward them to the cloud center, depending on whether the FNs are overloaded or not. By considering the fading channels between TNs and FNs, we mathematically characterize the energy consumption tradeoff between TNs and FNs by varying the broadcasting rate of TNs.