Patent ID: 7934244

Claim:
A method of transmitting a broadcast signal in a transmitter, the method comprising: pre-processing, at a preprocessor, first service data including audio or video data for a mobile service, wherein pre-processing first service data comprises: building, at a first encoder, a Reed Solomon (RS) frame, wherein building the RS frame comprises: performing RS encoding on the first service data and adding RS parity bytes to an RS frame payload including the first service data, and adding Cyclic Redundancy Check (CRC) syndrome checksum bytes to the RS-encoded RS frame payload; dividing, at an RS frame divider, the RS frame into a plurality of portions; forming, at a group formatter, data groups of the first service data, each data group including signaling information, known data sequences that have pre-determined values, and one of the plurality of portions, wherein the signaling information includes information indicating a number of the data groups to be transmitted during a transmission frame, and forming, at a packet formatter, first service data packets including the first service data, the signaling information and the known data sequences in the data groups; multiplexing, at a multiplexer, the first service data packets and second service data packets including second service data which includes audio or video data for a main service; performing, at a second encoder, systematic 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, at a transmission unit, a broadcast signal including the RS encoded first service data and the RS encoded second service data, wherein a collection of the formed data groups is transmitted during slots in the broadcast signal, the slots being 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 data groups.