Patent ID: 8495695

Claim:
A method of transmitting a broadcast signal in a transmitter, the method comprising: pre-processing first service data including audio data or video data for a mobile service via a preprocessor, wherein pre-processing the first service data comprises: block processing the first service data via a block processor, wherein block processing the first service data comprises: first converting data bytes of the first service data to data bits via a first converter; encoding the first converted data bits to output symbols via a first encoder; symbol interleaving the output symbols via a symbol interleaver; second converting the symbol interleaved symbols into data bytes of the first service data via a second converter; forming data groups via a group formatter, each data group including signaling information, known data sequences that have pre-determined values, and the first service data, wherein the signaling information includes information indicating a number of the data groups to be transmitted during a transmission frame, and forming first service data packets including data in the data groups via a packet formatter; multiplexing, via a multiplexer, the first service data packets and second service data packets, the second service data packets including second service data including audio data or video data for a main service; performing, via a second encoder, systematic Reed-Solomon (RS) encoding on the second service data in the multiplexed data packets and non-systematic RS encoding on the first service data in the multiplexed data packets; and transmitting a broadcast signal including the RS encoded first service data and the RS encoded second service data via a transmission unit, wherein a collection of the formed data groups is transmitted during slots in the broadcast signal, wherein the slots are basic time periods for multiplexing of the first service data and the second service data, and wherein the signaling information includes an identifier of the collection of the formed data groups.