  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 frequency-allocation schemes
to mitigate the interference and to increases 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.
