عنوان مقاله [English]
Traffic offloading (transferring a share of cellular network traffic to complementary network technologies such as Wi-Fi) is an economic and efficient mitigation for the ever-increasing congestion in cellular networks. In this regard, reducing fixed and variable costs of cellular operators in one side and providing some incentives for the users to participate in the offloading in the other side are among the main challenges to be addressed. In this way, delay tolerant offloading (in which users may tolerate some delay before receiving their needed data) is investigated and a new optimization mechanism in two stages is proposed. First, by utilizing user motion pattern prediction, a model is formulated to obtain the optimal placement of complementary WiFi networks and their bandwidth allocation. Second, cellular operator's overall variable cost (including data exchange and user incentive costs) is minimized. Minimizing the latter is performed using a reverse auction framework. Moreover, due to nonlinearity and high complexity of proposed models, heuristic algorithms are proposed to solve them. A numerical study and simulations of the algorithms show that the proposed mechanism outperforms previous methods in terms of balancing the load of cellular network and reducing overall cost of the cellular operators.