Data transmitting system, data transmitting method and base station

A base station used in a packet transmission system in which shared user data to be selectively received by a user are transmitted using a shared data channel from one or more base stations to one or more mobile stations, wherein the base station comprises:

• means configured to provide user control data associated with transmission of the shared user data;
• means configured to provide notification data that include notification information used to select the shared user data and group identification information for specifying the notification information;
• and
• means configured to generate an associated control channel that is associated with the shared data channel and includes the user control data and the notification data, the associated control channel and the shared data channel being transmitted from the base station to the mobile station.

A packet data transmission method of transmitting shared user data using a shared data channel from one or more base stations to one or more mobile stations, the shared user data being selectively received by a user, the method comprising the steps of:

• at the base station, providing user control data associated with the shared user data;
• at the base station, providing notification data that contains notification information used to select the shared user data and group identification information for specifying the notification information;
• at the base station, generating an associated control channel that includes the user control data and the notification data and is associated with the shared data channel;
• and
• transmitting the associated control channel together with the shared data channel from the base station to said one or more mobile stations.