MAC Location Services for IEEE802.11 Networks

This paper presents an IEEE802.11 MAC extension to include localization services in the wireless LAN networks, which lack of any support for such services neither at hardware level nor at network level. Independently from the method at the PHY layer used to estimate the distance, we propose an effective location management policy procedure at the MAC level. The algorithm is based on the distance estimation performed by, at least, three Base Stations to calculate the mobile user position using the well known triangulation process. We propose an innovative and efficient method based on both the IEEE802.11 PCF and DCF phases to track the user position at a constant rate according to the user speed. A complete simulation model has been developed in order to assess the maximum number of users traceable and to provide our algorithm efficiency and performance level.