An Evolutionary Game Theory Approach for Joint Offloading and Interference Management in a Two-Tier HetNet

In this paper, we present a price-based approach for offloading macro users to small-cells in a two-tier heterogeneous network (HetNet). We have constructively exploited the small-cell density in a HetNet to harness offloading opportunities for macro users (MUs), the goal of which is to solve two problems simultaneously. It aims to shun the MUs, who have a lower received data rate due to the interference perceived from the small-cell tier. The scheme also fends off congestion in a macrocell, by offloading macro users to the small-cell tier. We have proposed a novel threshold pricing scheme, which a macrocell adopts, with a view to influencing low data rate MUs to join a small-cell network. Small-cell networks also charge a price, which includes an access price and an interference compensation price, proportional to the number of MUs who choose the small-cells instead of the macrocellular network. We assume that the small-cells adopt existing cell range expansion techniques to accommodate MUs. We formulate an evolutionary game to model and analyze the behavioral dynamics of the large number of MUs under the proposed pricing strategies of both networks. Replicator dynamics is used to find the evolutionary equilibrium of the evolutionary game. Sequentially, we provide the proof of the existence, uniqueness and stability of the evolutionary equilibrium through extensive analysis. Numerical results are provided to demonstrate that the proposed pricing strategies are able to shape the network dynamics by fine-tuning the rate-threshold and price. The ability to control the macrocell population share by itself with an application of the proposed pricing scheme remains the prime contribution of this paper.