  Over the years, vertical handover necessity estimation has attracted the
interest of numerous researchers. Despite the attractive benefits of
integrating different wireless platforms, mobile users are confronted with the
issue of detrimental handover. This paper used extensive geometric and
probability analysis in modelling the coverage area of a WLAN cell. Thus,
presents a realistic and novel model with an attempt to minimize unnecessary
handover and handover failure of a mobile node (MN) traversing the WLAN cell
from a third generation (3G) network. The dwell time is estimated along with
the threshold values to ensure an optimal handover decision by the MN, while
the probability of unnecessary handover and handover failure are kept within
tolerable bounds. Monte-Carlo simulations were carried out to show the behavior
of the proposed model. Results were validated by comparing this model with
existing models for unnecessary handover minimization.
