Geofences based on RF fingerprints

Systems, apparatus and methods in a mobile device for creating and/or using a geofence are presented. When creating a geofence, a mobile device collects at least one RF fingerprint. Each RF fingerprint includes transmitter information from a plurality of transmitters. The transmitter information includes information identifying the transmitter (e.g., location or MAC address of the transmitter) referred to here as absolute information. The transmitter information may also include information indication a relative position of the mobile device with respect to the transmitter (e.g., RTT or RSSI) referred to here as relative information. The RF fingerprints are used to define a geofence. Granularity may further be used to define a geofence. A first mobile device creates the geofence and sends it to a second mobile device, which looks for the geofence. When using the geofence, a second mobile device may trigger an application when a breach of the geofence is detected.