Inbound Mobility Management on LTE-Advanced Femtocell Topology Using X2 Interface

The femtocell access point of LTE-Advanced system, which can be deployed under macrocell coverage, was applied to the paper. The paper consists of two analyses which are the interference impact by the femtocell and the macrocell at a user equipment and the load impact to the control plane in evolved packet core network by X2 and S1 handover signaling messages. On the results of investigations by performance simulations with regard to the receiving power and signal-to-noise ratio at a user equipment side, the unavailable zone to the inbound handover from macrocell to femtocell occurred due to a severe intercell interference depending on a femtocell topology. Therefore, we found that an intercell interference coordination between macrocell and femtocell in order to make an inbound handover is needed and that X2 interface is the better solution rather than S1 interface for an inbound handover by investigating the X2 and S1 handover procedure of 3GPP. Ultimately, it is shown that the X2 interface between macrocell and femtocell can play an important role in an high reliable inbound handover and a simple interference control implementation on femtocell environment.