ZiFi: wireless LAN discovery via ZigBee interference signatures

WiFi networks have enjoyed an unprecedent penetration rate in recent years. However, due to the limited coverage, existing WiFi infrastructure only provides intermittent connectivity for mobile users. Once leaving the current network coverage, WiFi clients must actively discover new WiFi access points (APs), which wastes the precious energy of mobile devices. Although several solutions have been proposed to address this issue, they either require significant modifications to existing network infrastructures or rely on context information that is not available in unknown environments. In this work, we develop a system called ZiFi that utilizes ZigBee radios to identify the existence of WiFi networks through unique interference signatures generated by WiFi beacons. We develop a new digital signal processing algorithm called Common Multiple Folding (CMF) that accurately amplifies periodic beacons in WiFi interference signals. ZiFi also adopts a constant false alarm rate (CFAR) detector t...

• Type: Conference
• Year: 2010
• Where: MOBICOM
• Authors: Ruogu Zhou, Yongping Xiong, Guoliang Xing, Limin Sun, Jian Ma
• Keywords: Communications, MOBICOM 2010, WiFi, Wifi Beacon, WiFi Networks