Self-organized distributed cooperative control of interference in femtocell networks

The scarcity of free bandwidth for new wide area wireless networks and the need to support bandwidth intensive applications drives the current need for femtocell technologies. A common requirement present in fourth generation systems is the inclusion of self-organizing technologies that facilitate deployment, operation and management of femtocells. As femtocells are designed to be installed by the user in unplanned locations it is critical to mitigate the interference created for macrocells as well as that between femtocells. In this article we propose employing distributed cooperative control theory to enable self organization of femtocell transmitters to mitigate interference via power control. We study how different types of controllers can be constructed, evaluate their performance and compare them against a closed solution based on Perron´s theorem. A clear advantage of the proposed approach is that it has been proven to converge under simple, realistic assumptions. We show how our solution mitigates both outdoor and indoor interference in different environments including those where femto transmitters are located far away from a cluster.