Apparatus and method for synchronizing net in unsymmetrical multimedia satellite communication system

PURPOSE: An apparatus and a method for synchronizing a net in a asymmetrical multimedia satellite communication system are provided to broadcast a net synchronizing information using an adaptation field sentence to all terminals and, continuously, maintain a net synchronization between a central station and a terminal using a program cluck standard value and a net synchronization information. CONSTITUTION: A transmission stream generating part(60) composes a packet for a net synchronization and outputs. A transmitting part(90) multiplexes an output of a large number of transmission stream generators, modulates this to broadcast through a satellite. A central station receiving and processing part(20) generates a standard timing signal from the received transmission stream. A receiving slot timing generating part(30) generates a receiving slot timing using a standard timing. A burst receiving part(40) of a synchronization type measures a receiving timing error of the burst using a receiving slot timing and provides to the transmission stream generating part. A terminal station receiving and processing part(110) generates a standard timing signal. A transmission slot timing generating part(120) modifies a timing generation time of a transmission slot. A burst transmitting part(130) of a synchronization type synchronizes a burst to a transmitting slot timing to transmit.