Vertical handoff scheme concerning mobility in the two-hierarchy network

In a two-hierarchy cellular network - comprised of a central macrocell underlaid with shorter range femtocell, seamless vertical handoff (VHO) is a challenging issue to be approached. With regard to VHO performance requirement in heterogeneous networks, there is a critical demand to develop schemes of the connection managements with synthetically considering additional factors, such as, monetary cost, offered services, user velocity, network conditions, and user preferences besides received signal strength (RSS). To achieve this, a new VHO decision method consisting of the handoff candidates picking and a well-defined objective function optimization is proposed in this paper. When the handoff candidates are picked, the practical constraints will be considered in the new scheme, including femtocell access manner, RSS, and UE velocity. The objective function combines multiple factors that the network operator concerns and thus owns good expansibility and portability. By applying this scheme, the optimal overall performance can be achieved in the integrated system of macrocell and femtocell access networks. Results based on the detailed performance evaluation demonstrate promoted efficacy of the proposed scheme compared to the traditional ones.