Exploiting Mobility Patterns to Reduce Re-Authentication Overheads in Infrastructure WLAN Networks

The current EAP-TLS standard accounts for authentication delays of the order of one second for infrastructure 802.11 networks. This delay is clearly unacceptable for maintaining the QoS requirements for a mobile station which have frequent handoffs to different regions. Pre-authentication schemes have been proposed to reduce these delays. However, most of these schemes suffer from an increased network message overhead since they fail to appropriately model the mobility of each individual user. In this paper, we exploit the notion of predictability in user mobility patterns and propose a set of novel proactive key distribution algorithms to achieve low latencies while minimizing the message overhead. Our schemes involve pre-distributing keys in fewer necessary access points (APs) as opposed to all neighboring APs. We evaluate the performance of our schemes for three different mobility models; (i) predictable motion (ii) changing predictable motion and (iii) random motion. Almost under all scenarios, our schemes indicate up to 70% message reduction, while maintaining similar latencies