Synchronization method and apparatus for broadcast multicast service

A method in which at least one base station provides broadcast multicast service, comprising:

• receiving a session start request message and information indicating a service start time;
• requesting an upper router to send a user packet for providing broadcast service corresponding to the session start request message;
• and
• receiving the user packet and transmitting the user packet to at least one user equipment so as to start broadcast service at the service start time.

A synchronization apparatus for broadcast multicast service, the synchronization apparatus controlling scheduling of at least one base station, comprising:

• a receiver configured to receive a session start request message, and to extract a service start setting time set to start broadcast service from the session start request message;
• a calculator configured to compare the service start setting time to a modification check time being a check time which is later than and closest to the service start setting time, among check times at which it is determined whether or not broadcast service has changed, the check times having a predetermined time interval, and to decide, if the modification check time is later than the service start setting time by a predetermined internal slack time period or more, the modification check time as a service start time at which broadcast service starts;
• and
• a communication unit configured to transmit information indicating the service start time to the base station.

A base station for providing a broadcast multicast service, comprising:

• a message receiver configured to receive a session start request message and information indicating a service start time from a Multi-Cell/Multicast Coordinate Entity (MCE);
• a broadcast service requesting unit configured to request a Multimedia Broadcast Multicast Service-Gateway (MBMS-GW) to send a user packet in order to provide broadcast service corresponding to the session start request message;
• and
• a radio resource allocating unit configured to receive the user packet and to transmit the user packet to at least one user equipment so as to start broadcast service at the service start time.