Analysis and Performance Evaluation of Wireless LAN Handover

Wireless LAN (WLAN) is a wireless network which provides connectivity in a limited area; IEEE 802.11 is the most widespread standard for wireless LANs. The paper, after a brief introduction on the WLAN technology, describes the handover procedure, the related security issues and the lab scenario measurement results. In the first part of the work, the value of path loss in an in-building line of sight condition has been estimated and the expression of the critical speed for a successful handover has been derived; the second part of the paper deals with handover latency measurements in a IEEE 802.11g WLAN lab scenario with PEAP/MSCHAPv2 authentication. The results show that the 802.1x authentication delay takes the longest time, and that it can be reduced through a pre-authentication mechanism which brings to a very short handover time, suitable even for real time services.