Handover Study Concerning Mobility in the Two-Hierarchy Network

Femtocell is an emerging technology aiming for a better indoor coverage. Due to its low costs, high grade of service, promotion of fixed-mobile convergence (FMC) and no change of core network, it has drawn close attention from the standardization organizations and the industrial field. In the two-hierarchy networks composed of traditional macro cellular networks and the embedded femtocell hotspots, moving mobiles will face up to the continual handovers when they pass along buildings. In this paper, handover algorithms considering signal strength and velocity are proposed using the mathematics concept of "set". Different handover methods are discussed and simulated. The results show that the proposed algorithms can obviously cut down unnecessary handovers compared with conventional soft handover on the same handover signal level limit. What\´s more, throughput of high speed mobiles and the total throughput of macro base station are increased.