Cost-Effective Frequency Planning for Capacity Enhancement of Femtocellular Networks

The femto-access-point, a low-cost and small-size cellular base-station, is envisioned to be widely deployed in subscribers homes, as to provide high data-rate communications with improved quality of service. As femtocellular networks will co-exist with macrocellular networks, mitigation of the interference between these two network types is a key challenge for successful integration of these two technologies. In particular, there are several interference mechanisms between the femtocellular and the macrocellular networks, and the effects of the resulting interference depend on the density of femtocells and the overlaid macrocells in a particular coverage area. While improper interference management can cause a significant reduction in the system capacity and can increase the outage probability, effective and efficient frequency allocation among femtocells and macrocells can result in a successful co-existence of these two technologies. Furthermore, highly dense femtocellular deployments—the ultimate goal of the femtocellular technology—will require significant degree of self-organization in lieu of manual configuration. In this paper, we present various femtocellular network deployment scenarios, and we propose a number of frequencyallocation schemes to mitigate the interference and to increase the spectral efficiency of the integrated network. These schemes include: shared frequency band, dedicated frequency band, sub-frequency band, static frequency-reuse, and dynamic frequency-reuse. We derive an analytical model, which allows us to analyze in details the users outage probability, and we compare the performance of the proposed schemes using numerical analysis.