An Improved Handoff Technique to Reduce Handoff Latency with help of GPS Technology

Due to rapid growth in IEEE 802.11 based Wireless Local Area Networks (WLAN), handoff has become a burning issue. A mobile node (MS) requires handoff when it travels out of the coverage area of its current access point (AP) and tries to associate with another AP. But handoff delays provide a serious barrier for such services to be made available to mobile platforms. Throughout the last few years there has been plenty of research aimed towards reducing the handoff delay incurred in the various levels of wireless communication. In this article we propose to minimize the handoff latency by minimizing the number of APs scanned by the mobile station (MS) during each handoff procedure. We assume hexagonal coverage area of an AP with the AP situated at the center. By GPS, we can note down the co-ordinates of the MS at any instant. Segmenting the hexagon into 6 segments with 600 coverage area for each, we determine the trajectory of the MS by GPS. Hence the direction of motion of the MS can be determined, which in turns gives the AP towards which the MS is heading towards. This reduces the number of APs to be scanned. Thus, on an overall basis, the handoff latency can be reduced by almost half to one third of its value.