A gateway receives network presence information regarding a mobile station. The network presence information is based, at least in part, on status messages that a network access server, such as a packet data serving node (PDSN), sends, for example, to an accounting server. The network presence information...http://www.google.com/patents/US7990986?utm_source=gb-gplus-sharePatent US7990986 - Method and system for identifying a mobile station to a content server
