Interference Mitigation in Two-Tier OFDMA Femtocell Networks with Differential Evolution

This paper addresses the cross-tier interference mitigation problem in two-tier OFDMA femtocell networks using power control. We model the objective of power control with utility functions for macrocell and femtocell, respectively. And we discuss the existence of optimal solutions to power control problems. Then a power control algorithm with Differential Evolution (DE) is developed to find the optimal power settings which maximize the utility function. Through numerical calculation, we study how to properly set the parameters of DE for our proposed utility functions. Furthermore, the performance of power control algorithm with different tunable coefficients of utility function is also analyzed by system level simulation. Simulation results show that our proposed algorithm can improve the outage and throughput performance of macro users with minor impact on femtocell users. Meanwhile, our proposed algorithm is easy to implement in distributed manner.