Minimization of Handoff Latency by Angular Displacement Method Using GPS Based Map
Handoff has become an essential criterion in mobile communication system especially in urban areas, owing to the limited coverage area of Access Points (AP). Handover of calls between two BS is encountered frequently and it is essentially required to minimize the delay of the process. Many solutions attempting to improve this process have been proposed but only a few use geo-location systems in the management of the handover. Here we propose to minimize the handoff latency by minimizing the number of APs scanned by the mobile node (MN) during each handoff procedure. We consider the whole topographical area as a two dimensional plane. 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 MN at any instant. Segmenting the hexagon into 6 segments with 60 0 coverage area for each, we determine the trajectory of the MN by GPS. Hence the direction of motion of the MN can be determined, which in turns gives the AP towards which the MN 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.
Keywords: IEEE 802.11, GPS (Global Positioning System), trajectory of MN, Neighbor APs, angular displacement.
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