Services based on the location of a mobile user as determined by using network and/or mobile-device-based technology. Technologies supporting this include cell of origin (also known as cell ID), AOA, time of arrival (TOA), EOTD and GPS or assisted GPS. GPS can be used without network modification but requires mobile devices to support GPS. In WLAN systems, location can be determined by triangulation between several access points. Location data can be used for a variety of services to mobile-device users, including advertisements, billing, information, tracking and safety. See also e911 and GPS.