Abstract: Fog computing extends the cloud-based service to the network edge and it can be deployed in various scenarios. Aiming to solve the problem of fog computation task offloading in dense heterogeneous cellular network, and make full and reasonable utilization of the computing resources of all fog nodes, this paper proposes a computation task offloading algorithm. Firstly, the feasibility, fairness and stability of fog node cooperation are modeled and designed. Secondly, the contribution degree and contribution ratio coefficient of cooperation are defined. Combined with the threshold of the remaining computing capacity and the threshold of the cooperative contribution degree of the fog nodes, a cooperative fog node selection algorithm is proposed. Finally, an optimization problem is proposed to minimize the weighted sum of the task execution energy consumption and the user's payment cost under the constraint of the maximum tolerable delay of the task, and the optimal unloading decision is obtained by combining the external penalty function method and Powell (direction acceleration) method. Simulation results show that the proposed algorithm can effectively reduce the total cost of dense heterogeneous cellular network, compared with some of the algorithms studied in this paper.

Key words: dense heterogeneous cellular network, fog computing, computation offloading, the contribution degree of cooperation