Delay-aware optimization of energy consumption for task offloading in fog environments using metaheuristic algorithms

Due to the limitations associated with the processing capability of mobile devices in cloud environments, various tasks are offloaded to the cloud server. This has led to an increase in the efficiency of mobile applications in the two decades since the advent of the cloud paradigm. However, task offloading may not be a suitable option for delay-sensitive mobile applications because the cloud server is usually located remotely from mobile users. To overcome this problem, fog computing, also known as “Cloud at the Edge”, has been introduced as a complementary solution. On the other hand, although fog computing brings computing and radio resources closer to mobile devices, fog nodes cannot adequately meet users’ needs due to limited computing resources. To minimize delays in responding to mobile users’ requests, it is necessary to establish a trade-off between local execution of requests on end-devices and the fog environment. In this paper, we present task offloading in the form of a multi-objective optimization problem with a focus on reducing both total power consumption of the system and the delay in executing tasks. Then, considering the NP-hardness of the problem, we solve it using two meta-heuristic methods, namely the non-dominated sorting genetic algorithm (NSGA-II) and the Bees algorithm. The simulation results supported the robustness of both meta-heuristic algorithms in terms of energy consumption and delay reduction. The proposed methods achieve a better tradeoff concerning both offloading probability and the power required for data transmission.