Backup Wi-Fi Ad-Hoc Network for Emergency Response in Scenarios with Sporadic Connectivity and Primary Users

Inter-agency emergency response operations are sometimes hindered by a lack of common communication technology or by circumstances that render their networks unusable. We present a protocol architecture based on ubiquitous WiFi terminals (smartphones) that could be used for backup communications when everything else fails. If WLAN primary users (access points) are present, the channel selection mechanism selects alternate channels without the need of a common control channel. To deal with a sparse and disconnected topology, our mission-aware delay-tolerant routing algorithm uses short-term contact prediction and otherwise distributes packets to disconnected subnets without network-wide flooding.