Macrocell base stations are the backbone of mobile communications. Since it can not be designed for perfect coverage, it was logical to develop alternative solutions that can simultaneously work with the macrocell. The latest solution for coverage within the closed area are femtocell systems incurred as a smaller version of picocells. The advantage of femtocells is primarily in their simplicity and ease of implementation. It is easy to integrate with existing mobile systems, and for their work one requires a common DSL or fiber-optic cable. It configures as basic home router. For users, this is the perfect solution for a better signal. But for femtocells to work undisturbed, it was necessary good planning with the existing network infrastructure and research in order to reduce interference between the various systems. This master thesis introduces the single femtocell through existing systems, 2G, 3G, 4G, WiMAX and processed appearance and resolve interference problems with existing systems as well as with the very femtocell.