Interference Mitigation in Cognitive Femtocells

Femtocells are expected to take a major role on increasing the data rates on cellular network access over the next years. However, femtocells pose significant challenges, especially in terms of interference management and mitigation. In femtocell scenario, the costs for tradional network planning, management and optimization can be prohibitive. Instead, self-optimization of an uncoordinated deployment should be considered. Cognitive Radio enabled femtocells are considered to be a promising solution to enable self-optimizing femtocells to effectively manage the inter-cell interference, especially in densely deployed femto scenarios. In this paper, two key elements of cognitive femtocells are combined: a power control algorithm and a fully distributed dynamic spectrum allocation method. The resulting solution was evaluated through system-level simulations and compared to the separate algorithms and fixed frequency reuses. The outage throughput performance of the combined algorithm exceeds all other options, proving the efficiency of the method in reducing inter-cell interference.