An efficient scanning group and order decision method using neighbor network information in wireless LAN

In the IEEE 802.11 WLAN, a mobile station (MS) performs a handover whenever it moves out of range of one access point (AP). However, channel scanning which discovers the new available APs is the dominating factor in handover latency, accounting more than 90% of overall latency. In order to reduce such a scanning latency, we focus on the method reducing the number of channels for the MS in handover process to scan. With the help of IEEE 802.21 information server (IS), a proper scanning order of channels is offered by the current AP. By using this scanning order, the passive scanning of a MS in normal operation enables the MS to filter out the unavailable channels, and thus to prepare the reliable group of channels to scan during the future handover process. Simulation results show that our proposed scanning group and order decision method reduces the scanning latency in handover process compared to the conventional scheme.