An Apple patent (number 20120302256 at the U.S. Patent & Trademark Office shows that the company is working on ways to identify and locate users on a mobile network.

A system and method of locating "friends" having mobile devices connected to a network and associated with a user account is disclosed. The method includes sending a request to a mobile device, the mobile device determining its present geographic location and responding to the requestor with this information. This information may be in the form of a coordinate location such as a GPS location or it may be in the form of a name that the mobile device owner assigned to a particular area (e.g., "home"). Having this location information, a user is able to view the location of the friend that is associated with the mobile device.

Here's Apple's background on the invention: "Mobile devices have been adapted to a wide variety of applications, including computing, communication, and entertainment. Through recent improvements, mobile devices can now also determine their geographic location by either using a built-in global position system (GPS) antenna or extrapolating its location from the signals it receives through the network of fixed-location cellular antennas. Thus, a user may be able to use the mobile device to determine his or her location.

"A mobile device user may wish to have friends or family members know of his or her location and likewise, he or she may like to know the location of his or her friends or family members. Several known systems perform such services. However, one drawback of such services is that determining locations, particularly when using GPS devices, may consume a lot of power.

"Balancing battery life and mobile device performance is a chief concern for mobile device makers, and location aware programs are a big part of those concerns. Specifically, applications that must make frequent requests of a GPS device consume a lot of power. Such applications include mapping programs, and social location aware applications such as FourSquare and Google Latitude which allow a user to share his location with a server so that authorized friends can view the user's location on their mobile devices.

"Frequently, such services require an application running on the user's mobile device to periodically activate the GPS device, learn the user's location, and update the server. Such repeated use of the GPS device drastically reduces the battery life of the mobile device."

The inventors are Raghu Pai, Timothy S. Hurley, Patrice Olivier Gautier, Karthik Narayanan, Murthy Parthasearathi and Maxime Veron.