Emergency service in Wi-Fi networks without access point association

Emergency "911" service is a critical function provided in the PSTN, cellular and VOIP networks. Wi-Fi, despite its growing importance, has no such service. In this paper, we develop a 911-like service for Wi-Fi capable devices, enabling them to send emergency messages through any available hotspot or access point. Our service makes use of existing 802.11 management frames and does not require the client device to associate or authenticate with the access point; this makes it available even on protected networks to which the client would not normally have access, even encrypted ones. This design ensures maximum potential reach and usability, and helps to increase public safety.