Minimization of Handoff Failure Probability by Using Mother Cell Child Cell Concept

Abstract

Presently, IEEE 802.11 based wireless local area networks (WLAN) have been widely deployed for business and personal applications. The main issue regarding wireless network technology is handoff or hand over management, especially in urban areas, due to the limited coverage of access points (APs) or base stations (BS). When a mobile station (MS) moves outside the range of its current access point (AP) it needs to perform a link layer handover. But handoff failure probability provides a serious barrier for such services to be made available to mobile platforms. Throughout the last few years plenty of research works had been done to reduce the hand off failure probability. Whereas, some of them have applied efficient channel allocation techniques, keeping the total number of channels constant. In this paper we also propose a method to minimize the handoff failure probability by increasing the total number of channel with help of Mother cell Child cell concept. Here we consider a larger hexagonal cell which almost covers up the whole region of a seven cell cluster. We will say this larger cell as the Mother cell and the smaller cells are the Child cells. The mother cell AP has a higher signal range than that of child cell as it covers larger area than the child cell. The Mother cell AP will only perform the handoff job whereas the child cell AP will perform both the originating and the handoff calls. Thus the total number of channel increases without any channel interference. This in turn, reduces the handoff failure probability. Simulation results yield that the proposed mechanism outperforms the usual channel allocation technique.