The present invention relates to synchronizing a terminal and a server in a shadow area of service in a push-to-talk (PTT) service system. An alive report packet is periodically transmitted to a server by a terminal having no permission to send a talk burst. A talk burst idle packet is periodically transmitted...http://www.google.fr/patents/US7792540?utm_source=gb-gplus-shareBrevet US7792540 - Synchronizing push to talk service in wireless communication system
Synchronizing push to talk service in wireless communication system
