Capacity optimization of femtocell networks

Femtocells are short-range devices deployed to provide increased coverage and capacity in a small area. They offer a way to increase the capacity of a cellular network by relaying cellular traffic to the wired network. In this paper, we address the problem of optimizing the overall capacity of a femtocell network, as defined by Shannon's law and physical interference, by appropriate power and channel assignment to the femtocells. In particular, we design an approximation algorithm for the objective of maximizing the total network capacity, for large uniform networks with arbitrary coverage regions. We also consider the second objective of maximizing the minimum capacity at a femtocell in the network, and design an algorithm for arbitrary networks which has an appropriate performance guarantee if there is a lower-bound on the distance of any two femtocells. Through simulations, we demonstrate the performance of our designed algorithms by comparing them with a bound on the optimal values.