IEEE 802.11 based wireless networks are widely deployed in densely populated areas such as university campuses, airports, offices, cafeterias, etc. Their popularity is rising because of their low cost and high bandwidth except that they cover small coverage areas. In order to cover large areas several access points (AP) are required, which makes it disruptive technology. During roaming, the mobile station (STA) makes frequent handoffs (HO) between APs. Scanning delay during the HO process is quite high, which makes it unsuitable for real-time applications such as VoIP (voice over internet protocol). In this article, we present a technique to reduce the MAC layer HO delay. Using an analytical model, we discuss our technique along with numerical results, and show that the scanning delay is within VoIP constraint which is a major obstacle for WLANs to be used for real-time applications.
['Rizwan Khan', 'Sonia Aissa', 'Charles L. Despins']
MAC layer handoff algorithm for IEEE 802.11 wireless networks