Multicast communication method in a CDMA mobile communication system

A multicast communication method in a CDMA mobile communication system, which comprises a plurality of mobile subscribers and a plurality of base station systems including anchor base stations and branch base stations that are communicatively connected to said mobile subscribers by radio channels, said method comprising:

• outputting information regarding a multicast transmission to be output, the information including a designated area in which the multicast transmission is to be broadcast;
• transferring the information regarding the multicast transmission to one or more of said anchor base stations corresponding to the designated area;
• informing, by said one or more anchor base stations to one or more of said branch base stations adjacent to said one or more anchor base stations, a starting of information transmission of the multicast transmission;
• and
• notifying, by said one or more branch base stations to at least one of said mobile subscribers in a radio transmission range of said one or more branch base stations, a starting of information transmission of the multicast transmission;
• and
• transmitting, over a multicast channel at a time corresponding to the starting of information transmission, multicast data to said at least one of said mobile subscribers.

A multicast communication system in a mobile communication system, comprising:

• at least one mobile subscriber;
• and
• at least one base station system, communicatively connected to said mobile subscriber by radio channels, comprising:
• receiving means for receiving a request regarding multicast communication from a mobile switching center;
• sending means for sending a notification of starting said multicast communication to said mobile subscriber after said receiving means receives said request;
• and
• transmitting means for transmitting multicast data to said mobile subscriber.

A base station system, comprising:

• receiving means for receiving a request regarding multicast communication from a mobile switching center;
• sending means for sending a notification of starting said multicast communication to a mobile subscriber, said mobile subscriber being connected with said base station system via radio channels, after said receiving means receives said request;
• and
• transmitting means for transmitting multicast data to said mobile subscriber.

A CDMA mobile communication system, comprising:

• a plurality of mobile subscribers and a plurality of base station systems including anchor base stations and branch base stations that are communicatively connected to said mobile subscribers by radio channels;
• means for outputting information regarding a multicast transmission to be output, the information including a designated area in which the multicast transmission is to be broadcast;
• means for transferring the information regarding the multicast transmission to one or more of said anchor base stations corresponding to the designated area;
• means for informing, by said one or more anchor base stations to one or more of said branch base stations adjacent to said one or more anchor base stations, a starting of information transmission of the multicast transmission;
• means for notifying, by said one or more branch base stations to at least one of said mobile subscribers in a radio transmission range of said one or more branch base stations, a starting of information transmission of the multicast transmission;
• and
• means for transmitting, over a multicast channel at a time corresponding to the starting of information transmission, multicast data to said at least one of said mobile subscribers.