  Integrated femtocell/macrocell networks, comprising a conventional cellular
network overlaid with femtocells, offer an economically appealing way to
improve coverage, quality of service, and access network capacity. The key
element to successful femtocells/macrocell integration lies in its
self-organizing capability. Provisioning of quality of service is the main
technical challenge of the femtocell/macrocell integrated networks, while the
main administrative challenge is the choice of the proper evolutionary path
from the existing macrocellular networks to the integrated network. In this
article, we introduce three integrated network architectures which, while
increasing the access capacity, they also reduce the deployment and operational
costs. Then, we discuss a number of technical issues, which are key to making
such integration a reality, and we offer possible approaches to their solution.
These issues include efficient frequency and interference management, quality
of service provisioning of the xDSL-based backhaul networks, and intelligent
handover control.
