Handover in UMTS Networks with Hybrid Access Femtocells

Femtocells enable in-home cell phone coverage and provide access to high speed wireless broadband services. The Femtocell network architecture is very different from the existing based on the UMTS macrocell network architecture. Hence, a modified handover procedure for existing networks is needed to support macrocell/ femtocell integrated networks. Voice call services are an essential part of mobile communications and studies of mobile usage show that more than 50 percent of all voice calls are placed indoors. Frequent and unnecessary handovers are another problem of heterogeneous network environments. In this paper, we propose a modified handover procedure for voice call service between 3GPP UMTS-based macrocell and femtocell networks. And Call Admission Control (CAC) to reduce the unnecessary handover in the hybrid access mode is proposed.