A New Pre-authentication Scheme for IEEE 802.11i Wireless LAN Network

As 802.11 Wireless LAN network is vulnerable to many security attacks, a complicated authentication mechanism was developed in IEEE 802.11i to enhance the WLAN network security. Unfortunately, the original 802.11i authentication procedure takes some time to complete and it will significantly affect the quality of service offered to mobile users who may handover between several access points. The existing pre-authentication scheme can shorten the authentication time remarkably, but it suffers from the unnecessary signalling overhead which may be a heavy burden to the network. In this paper, we propose to improve the preauthentication mechanism via reducing the signalling overhead. In our scheme, the mobile user will initiate the pre-authentication with a neighbouring access point only when he is really approaching that particular access point. Therefore, many unnecessary preauthentication signalling overheads can be avoided. Preliminary simulation results show that signalling overhead can be reduced by 50% while still maintaining short authentication delay.