Performance analysis of fast initial link setup for IEEE 802.11ai WLANs

The IEEE 802.11ai is an upcoming fast initial link setup (FILS) amendment that could enable a STA to achieve secure link setup in less than 100 ms. A successful link setup process will then allow the STA to send IP traffic with a valid IP address through the AP. In this paper, we first present a performance analysis on how well the legacy 802.11 can support FILS. We then demonstrate that the rate at which the medium saturates is mainly dependent on the offered load which has strong dependencies on the active scan rates (i.e., amount of transmitted probe request frames) and number of responding APs (i.e., amount of transmitted probe response frames) among others. Moreover, the average active scanning duration per channel could be maintained below 5 ms provided the medium is not saturated. Our results also indicate that a combination of the enhanced distributed channel access (EDCA) procedure and the proposed active scanning enhancements provides at least 20% and up to 250% improvements in supporting the functional requirements of FILS as compared to the 802.11 EDCA and legacy distributed coordination function (DCF), respectively.