IM-Torch: Interference Mitigation via Traffic Offloading in Macro/Femtocell+WiFi HetNets

Interference management is a hot issue in Heterogeneous Networks (HetNets), which is very crucial for the performance promotion in heterogeneous cellular networks with full frequency reuse. Focusing on mitigating the interference between Macrocell and Femtocell, we propose the IM-Torch (Interference Mitigation via Traffic Offloading in Macro/Femtocell + WiFi Heterogeneous Networks) scheme to handle this problem via traffic offloading. We formulate it as a Mixed Integer Nonlinear Program which is hard to solve, and design a two-step heuristic algorithm to solve this problem. In the first self-scheduling step, Femtocell tries to reallocate the power and PRBs (Physical Resource Blocks) for HUEs (Home User Equipment) to mitigate the interference. After the failure of the first step, Femtocell offloads some necessary HUEs with data services to WiFi and re-adjusts the resources for HUEs to alleviate the interference. The analysis and simulations validate that IM-Torch scheme can greatly alleviate the interference in HetNets and thus improve the system total throughput of Femtocell while guarantee the QoS of Macrocell and HUEs with real time applications.