The invention relates to a transmitting system, comprising an SNS client that receives SNS messages from at least one SNS server, and a transmitter which transmits a broadcast signal, including the SNS messages and mobile service data, for a mobile broadcast. The transmitter includes: an RS frame encoder, which performs RS encoding and CRC encoding on the mobile service data for the mobile broadcast so as to build RS frames, and divides each RS frame into a plurality of portions; a group-forming unit, which forms data groups that contain each of the plurality of portions, and which adds known data sequences and signaling data to each data group; an inter-leaver for interleaving data of the data groups; and a trellis encoding unit for trellis-encoding the interleaved data.

The present technology relates to a transmission device, a transmission method, a reception device, and a reception method capable of ensuring good communication quality in data transmission using an LDPC code.

In group-wise interleaving in which an LDPC code with a code length N of 69120 bits is interleaved in units of bit groups of 360 bits, an (i+1)th bit group from a head of the LDPC code is set as a bit group i, and a sequence of bit groups 0 to 191 of the 69120 bit LDPC code is interleaved into a predetermined sequence. In the group-wise deinterleaving, the sequence of the LDPC code after the group-wise interleaving is returned to the original sequence. The present technology can be applied to, for example, a case of performing data transmission or the like using an LDPC code.

The present invention provides a method of transmitting broadcast signals. The method includes, formatting, by an input formatting block, input streams into plural PLPs(Physical Layer Pipes); encoding, by an encoder, data in the plural PLPs; time interleaving, by a time interleaver, the encoded data in the plural PLPs, wherein the time interleaving includes: cell interleaving, by a cell interleaver, the encoded data by permuting cells in a FEC(Forward Error Correction) block in the plural PLPs; frame mapping, by a framer, the time interleaved data onto at least one signal frame; and waveform modulating, by a waveform block, the mapped data in the at least one signal frame and transmitting, by the waveform block, broadcast signals having the modulated data.

The present invention provides a method of transmitting broadcast signals. The method includes, formatting, by an input formatting block, input streams into plural PLPs (Physical Layer Pipes); encoding, by an encoder, data in the plural PLPs; time interleaving, by a time interleaver, the encoded data in the plural PLPs, wherein the time interleaving includes: cell interleaving, by a cell interleaver, the encoded data by permuting cells in a FEC (Forward Error Correction) block in the plural PLPs; frame mapping, by a framer, the time interleaved data onto at least one signal frame; and waveform modulating, by a waveform block, the mapped data in the at least one signal frame and transmitting, by the waveform block, broadcast signals having the modulated data.

A broadcast signal receiver is disclosed. A broadcast signal receiver according to the present invention comprises a synchronization/demodulation module carrying out signal detection and OFDM demodulation on a received broadcast signal; a frame parsing and deinterleaving module parsing and deinterleaving a signal frame of the broadcast signal; a demapping and decoding module converting data of at least one Physical Layer Pipe (PLP) of the broadcast signal into a bit domain and performing FEC decoding on the converted data; and an output processing module receiving data of the at least one PLP and outputting the received data into a data stream.

A transmitting system, a receiving system, and a method of processing broadcast signals are disclosed. The method for processing a broadcast signal in a broadcast receiver comprises receiving a DTV signal including a data group, the data group including mobile service data, segmented known data sequences, long known data sequences and transmission parameter data, compensating carrier frequency offset of the DTV signal and channel-equalizing the carrier frequency offset compensated DTV signal using at least one of the long known data sequences and segmented known data sequences in the data group of the DTV signal, wherein the channel-equalizing includes performing a Error Correction (FEC) decoding on data located between the segmented known data sequences, and estimating Channel Impulse Response (CIR) using the FEC decoded data as known data.

A method and an apparatus for transmitting broadcast signals thereof are disclosed. The apparatus for transmitting broadcast signals comprises an encoder for encoding DP (Data Pipe) data corresponding to each of a plurality of DPs, a mapper for mapping the encoded DP data onto constellations, a time interleaver for time interleaving the mapped DP data at DP level, a frame builder for building at least one signal frame including the time interleaved DP data, a modulator for modulating data in the built at least one signal frame by an OFDM (Orthogonal Frequency Division Multiplex) scheme and a transmitter for transmitting the broadcast signals having the modulated data.

A broadcast signal transmitter is disclosed. A broadcast signal transmitter according to an embodiment of the present invention comprises an input formatting module configured to perform baseband formatting and to output at least one PLP (Physical Layer Pipe) data; a BICM (Bit Interleaved Coded Modulation) module configured to perform an error correction process on the PLP data; a framing and interleaving module configured to interleave the PLP data and to generate a signal frame; and a waveform generating module configured to generate a broadcast signal by inserting a preamble into the signal frame and performing OFDM modulation.

A method for transmitting broadcast signals including encoding service data, mapping the encoded service data, and time interleaving the mapped service data. The time interleaving including block interleaving the mapped service data by writing cells of the mapped service data in a memory and reading the cells in the memory and spreading out the block interleaved service data over at least one signal frame. At least one Forward Error Correction (FEC) Block is included in at least one time interleaving (TI) Block for interleaving, and a number of FEC Blocks varies between TI Blocks. A virtual FEC Block is included ahead of the at least one FEC Block and virtual cells belonging to the virtual FEC Block are skipped during the reading. The method further includes modulating the time interleaved service data by an Orthogonal Frequency Division Multiplex (OFDM) scheme, and transmitting the broadcast signals carrying the modulated service data.

A broadcast signal receiver is disclosed. A broadcast signal receiver according to the present invention comprises a synchronization/demodulation module carrying out signal detection and OFDM demodulation on a received broadcast signal; a frame parsing and deinterleaving module parsing and deinterleaving a signal frame of the broadcast signal; a demapping and decoding module converting data of at least one Physical Layer Pipe (PLP) of the broadcast signal into a bit domain and performing FEC decoding on the converted data; and an output processing module receiving data of the at least one PLP and outputting the received data into a data stream.