A mobile communication system using a push to talk (PTT) scheme for providing a location based service (LBS) is provided. The system comprises a positioning server for confirming requested location information and transmitting subscriber information corresponding to the requested location information...http://www.google.co.uk/patents/US20060046759?utm_source=gb-gplus-sharePatent US20060046759 - Mobile communication system using push to talk scheme for supplying location based service and method therefor
