Vertical Handover Decision in Heterogeneous Wireless Networks with Femtocells

The implementation of small base stations, known as femtocells, can significantly improve network performance. Nevertheless, the inherent problem of the femtocells consists in significant amount of initiated handovers that could decrease a quality of service. This issue is further emphasized if the femtocells and the macrocells utilize different access technology, as vertical handover between them introduces longer interruption in the communication. Still, performing vertical handover can be profitable if other technology can offer higher quality of service. This paper contemplates three vertical handover decision strategies formerly considered for networks without femtocells and analyzes their performance if the femtocells are deployed. Since these strategies either introduce long interruption duration, high degradation of quality of service, or both, we also propose new vertical handover strategy considering femtocells features, such as small coverage and their vast deployment. Analytical evaluations and simulation results indicate that the proposed strategy can guarantee the highest quality of service for all considered performance metrics.