An Analysis of Handoff in Multi-band 802.11 Networks

The availability of public access WLANs (Wireless LANs) is growing with many cities now announcing municipal city-wide networks. This opens a new realm of possible applications such as telephony and gaming. However, before many of these applications can become widespread, the issue of mobility must be solved. Currently, the time required for wireless clients to handoff or transition their connection between APs (Access Points) is too long, causing call dropouts. This study investigates a specific aspect of handoff known as scanning. Improvements to current scanning mechanisms are proposed and tested in a variety of experiments. In addition, our experimental approach reveals previously unknown scanning issues in 802.11 networks.