Digital broadcasting system and method of processing data
View Patent ↗A digital broadcast receiving system includes a known data detector, a carrier recovery unit, and a timing recovery unit. The known data detector may detect known data information inserted and transmitted from a digital broadcast transmitting system and using the known data information to estimate initial frequency offset. The carrier recovery unit may obtain initial synchronization by using the initial frequency offset, and may detect frequency offset from the received data by using the known sequence position indicator so as to perform carrier recovery. The timing recovery unit may detect timing error information from the received signal by using the known sequence position indicator so as to perform timing recovery.
1. A method for processing digital broadcast data in a digital broadcast transmitter, the method comprising:
randomizing mobile service data;
performing Cyclic Redundancy Check (CRC) encoding on the randomized mobile service data;
performing encoding on the CRC-encoded mobile service data at a first code rate;
performing encoding on transmission parameters at a second code rate;
block interleaving the mobile service data encoded at the first code rate; and
convolutional interleaving the block-interleaved mobile service data.
2. The method of claim 1 , further comprising:
forming data groups including the mobile service data encoded at the first code rate,
wherein each of the data groups comprises a first region and a second region,
wherein the first region comprises:
an Nth segment comprising K mobile service data bytes,
an (N+1)th segment comprising L mobile service data bytes, and
an (N+2)th segment comprising M mobile service data bytes,
wherein the second region comprises:
an Oth segment comprising X mobile service data bytes,
an (O+1)th segment comprising Y mobile service data bytes, and
an (O+2)th segment comprising Z mobile service data bytes,
wherein the variables K, L, M, N, O, X, Y, and Z are integers greater than 0, and
wherein K<L<M, X=Y=Z, and N<O.
3. The method of claim 1 , further comprising:
performing Reed-Solomon (RS) encoding on the randomized mobile service data to build an RS frame,
wherein the RS frame comprises:
an RS frame payload including the randomized mobile service data;
RS parity data added at bottom ends of columns of the RS frame payload; and
CRC data added at right ends of rows of the RS frame payload.
4. The method of claim 3 , wherein the transmission parameters include information for indicating a number of bytes of the RS parity data per RS frame column.
5. The method of claim 1 , wherein the transmission parameters include information to identify a size of CRC data when the CRC-encoding is performed.
6. The method of claim 1 , further comprising:
multiplexing mobile service data packets and main service data packets, wherein the mobile service data packets include the mobile service data and the main service data packets include main service data.
7. The method of claim 6 , further comprising:
randomizing all data in the main service data packets of the multiplexed data packets; and
performing RS encoding on the main service data packets in which all data are randomized.
8. A digital broadcast transmitter for processing digital broadcast data, the digital broadcast transmitter comprising:
a first randomizer to randomize mobile service data;
a first encoder to perform Cyclic Redundancy Check (CRC) encoding on the randomized mobile service data;
a second encoder to perform encoding on the CRC-encoded mobile service data at a first code rate and to perform encoding on transmission parameters at a second code rate;
a first interleaver to block interleave the mobile service data encoded at the first code rate; and
a second interleaver to convolutional interleave the block-interleaved mobile service data.
9. The digital broadcast transmitter of claim 8 , further comprising:
a group formatter to form data groups including the mobile service data encoded at the first code rate,
wherein each of the data groups comprises a first region and a second region,
wherein the first region comprises:
an Nth segment comprising K mobile service data bytes,
an (N+1)th segment comprising L mobile service data bytes, and
an (N+2)th segment comprising M mobile service data bytes,
wherein the second region comprises:
an Oth segment comprising X mobile service data bytes,
an (0+1)th segment comprising Y mobile service data bytes, and
an (0+2)th segment comprising Z mobile service data bytes,
wherein the variables K, L, M, N, O, X, Y, and Z are integers greater than 0, and
wherein K<L<M, X=Y=Z, and N<O.
10. The digital broadcast transmitter of claim 8 , wherein the first encoder further performs Reed-Solomon (RS) encoding on the randomized mobile service data to build an RS frame, and
wherein the RS frame comprises:
an RS frame payload including the randomized mobile service data;
RS parity data added at bottom ends of columns of the RS frame payload; and
CRC data added at right ends of rows of the RS frame payload.
11. The digital broadcast transmitter of claim 10 , wherein the transmission parameters include information for indicating a number of bytes of the RS parity data per RS frame column.
12. The digital broadcast transmitter of claim 8 , wherein the transmission parameters include information to identify a size of CRC data when the CRC-encoding is performed.
13. The digital broadcast transmitter of claim 8 , further comprising:
a multiplexer to multiplex mobile service data packets and main service data packets, wherein the mobile service data packets include the mobile service data and the main service data packets include main service data.
14. The digital broadcast transmitter of claim 13 , further comprising:
a second randomizer to randomize all data in the main service data packets of the multiplexed data packets; and
a third encoder to perform RS encoding on the main service data packets in which all data are randomized.