Offloading in HetNets between two mobile network operators

Heterogeneous networks, where small cells are deployed over the conventional macrocell networks provide a fast, flexible, cost-efficient, and fine-tuned design and expansion for existing cellular wireless networks to satisfy the ever increasing demand for network capacity. In HetNets, small cells offload users and their associated traffic from congested macrocells to provide better service to users. More and more mobile operators are setting up their Hetnets. However due to the uncertain user demand and the unplanned deployment of base stations, some mobile network operator's base stations, especially macrocells, are very likely to be overloaded. To avoid the issues mentioned above, in this paper, we proposed an efficient alogrithm to solve the user offloading problem between different mobile network operators. The typical example is that an overloaded mobile network operator(OMNO)'s macrocell is surrounded with another mobile network operator(AMNO)'s small cells. The macro of OMNO offloads some users to the small cells of AMNO to guarantee the quality of users. Meanwhile, the small cells get additional revenue from the offloaded users, then the AMNO shares the interest with the OMNO. However, the proper number of offloading users, bandwidth leasing, transmit power levels of small cells and the revenue sharing factor are difficult to obtain. To explore the effect of operators, we formulate a two-layered game which consists of the bottom Stackelberg game and the top Nash bargaining game. Then, we solve the two-layered game with KKT condition and get the final solutions which is stable and optimal.