Abstract

The next generation wireless networks generally called 4G networks will most likely be actualized by the integration of present day available heterogeneous wireless networks. Integration of these networks will largely depend on the process of Vertical Handoff (VHO). VHO occurs when an active communication session is transferred between different heterogeneous radio access technologies. Several algorithms have been proposed in literature to implement the decision phase of VHO, some of which are discussed in this paper. Most of these decision algorithms in literature were not tested or evaluated to show their effect on handoff stability. This paper clearly shows how an enhanced decision algorithm (EDA) that considers four different decision metrics provides better handoff stability than other decision algorithms that lay priority on available bandwidth to make handoff decision. This is because the available bandwidth may, sometimes, fluctuate rapidly thereby making the VHO algorithm unstable. Our EDA introduced a technique that tapers this effect.

Key words: Vertical Handoff, enhanced decision algorithm, algorithms, networks.