Patent ID: 8396470

Claim:
A method for determining the availability of a mobile communications device on a network, the method comprising: predicting, using tracking data for the mobile communications device, the mobile communications device being configured to communicate using a plurality of communications services including at least one of instant messaging and text messaging, that the mobile communications device will cross a predefined service boundary, the predefined service boundary defining a locus of locations where a change in service identified by a plurality of criteria is expected to occur and is determined from a plurality of data sets received from a plurality of mobile communications devices, the plurality of data sets comprising location data, associated received signal strength data, and carrier data; and in response to said predicting, issuing at the mobile communications device, for receipt by a user of the mobile communications device, a notification associated with crossing the predefined service boundary, the notification comprising an indication of the availability of the mobile communications device for either said instant messaging or text messaging using one of the plurality of communications services, a format of the notification being selected according to a travelling speed of the mobile communications device determined from the tracking data.