Femtocell is an emerging technology for expanding cell coverage and increasing data rate, and its users deploy in their own premises by themselves. Therefore, femto base stations cannot go through manual cell planning procedure as the mobile communication base stations do. Femto base station sets its parameters, such as transmit power or pilot power, considering the surrounding radio environment. Due to its automated cell planning and parameter setting, leakage of the power to the outside of a house can occur and lead to highly increased number of unwanted handover events of macrocell users, which will finally lead to higher call drop probability. In this paper, we propose a coverage self-optimizing scheme to decrease the call drop probability in a real residential scenario. Our proposed scheme prevents unwanted handovers and comprehensive simulation results show that it improves performance of network in terms of handover and call drop probability.