Distributed user association and interference coordination in HetNets using Stackelberg game

In heterogeneous networks (HetNets), user association is introduced to encourage more users to connect to lightly loaded small cells. This is known as data offloading. However, this may result in that small cells usually sacrifice their own users´ performances since the offloaded macro users consume the resources of small cells. In this paper, we aim to improve the performances of both macrocell and small cells by channel assignment, biasing and power allocation in a distributed manner. The joint problem is modeled as a Stackelberg game. As the leader, the macrocell keeps silent on some channels for reducing interference to motivate the small cells to adapt macro users. As the followers, the small cells operate with biasing to accommodate macro users. Meanwhile, both the macrocell and small cells optimally allocate the transmit power over channels. We propose efficient algorithms for the macrocell and small cells making strategies. Furthermore, we prove that the proposed algorithms can lead to an equilibrium of the game. Simulation results show that the proposed methods significantly improve the network performances, compared with the existing methods.