Mobility robustness optimization in self-organizing LTE femtocell networks

Femtocell is a promising solution for enhancing the indoor coverage and capacity in wireless net- works. However, for the small size of femtocell and potentially frequent power on/off, existing han- dover schemes may not be reliable enough for femtocell networks. Moreover, improper handover parameters settings may lead to handover failures and unnecessary handovers, which make it neces- sary to enhance the mobility robustness for femtocells. In this article, we propose a gradient method and cost function-based mobility robustness optimization scheme for long term evolution (LTE) fem- tocell self-organizing networks. Moreover, signalling overhead of the scheme is analyzed. Simulation results show that the proposed scheme has a better performance than the fixed parameters method in terms of reduced the number of handover failures and unnecessary handovers with limited signalling modifications.