Patent ID: 8437331

Claim:
A method for transmitting a broadcast signal in a transmitter, the method comprising: encoding mobile data for forward error correction (FEC); forming a data group including the encoded mobile data and known data sequences; forming a specified number of mobile data packets and a first scalable number of mobile data packets using data in the data group; multiplexing the formed mobile data packets and a second scalable number of main data packets, wherein a sum of the first and second scalable numbers is equal to a specified value; interleaving data in the multiplexed main and mobile data packets; and transmitting the interleaved data, wherein the interleaved data are transmitted within a slot corresponding to a time period, wherein the second scalable number is ‘9’ or ‘0’ (zero), and when the second scalable number is ‘9’, the method further comprises: randomizing main data in the main data packets in a randomizer: and performing systematic Reed-Solomon (RS) encoding on the main data and non-systematic RS encoding on the mobile data in the mobile data packets in an RS encoder.