Digital broadcast system in passive optical network

An optical network unit (ONU), comprising:

• a data separator which receives a signal input to the ONU and separates the signal into an Ethernet frame for data service and an Ethernet frame for digital broadcast service;
• a channel request processor which receives, by using a part of bandwidth assigned for an existing line, a user's channel selection request information and user identification (ID) information from an optical network terminal (ONT) provided in the user's location;
• a digital broadcast processor which receives an MPEG stream containing all of the digital broadcast channels transmitted from a remote digital broadcast output unit over an Ethernet-passive optical network (E-PON), demultiplexes a plurality of Ethernet frames corresponding to all of the of the digital broadcast channels, and transmits, in response to the user's channel selection, one of the demultiplexed Ethernet frames that is corresponding to the digital broadcast channel selected by the user, to the user's ONT;
• and
• an Ethernet switch which transmits the Ethernet frame for the digital broadcast channel selected by the user to the user's ONT according to header information of the Ethernet frame;
• and
• wherein the digital broadcast processor further comprises:
• an Ethernet frame generator, in response to the user channel selection, to encapsulate the MPEG stream corresponding to the digital broadcast channel selected by the user in the Ethernet frame for the digital broadcast channel and to include the user's address as a destination address.