Apparatus and method for sending and receiving broadcast signals
A broadcast signal transmitter is disclosed. A broadcast signal transmitter according to an embodiment of the present invention comprises an input formatting module performing baseband formatting and outputting at least one Physical Layer Pipe (PLP) data; a BICM module error-correction processing the PLP data; a framing & interleaving module interleaving the PLP data and generating a signal frame; and a waveform generating module inserting a preamble into the signal frame and generating a broadcast signal by performing OFDM modulation.
1. A broadcast signal transmitter comprising:
an input formatter configured to input process input data and to output at least one Physical Layer Pipe (PLP) data;
a Bit Interleaved Coded Modulation (BICM) encoder configured to perform error correction processing on the PLP data;
a framer configured to generate a signal frame comprising the PLP data; and
a waveform generator configured to Orthogonal Frequency Division Multiplexing (OFDM)-modulate the signal frame and to generate a transmitting signal,
wherein the signal frame comprises a preamble and at least one subframe, and
wherein the at least one subframe includes at least one subframe boundary symbol, the subframe boundary symbol being a first symbol or a last symbol of the at least one subframe and the subframe boundary symbol has a greater scattered pilot (SP) density than data symbols of the subframe, and
wherein at least one of a last symbol of an immediately preceding subframe or a first symbol of an immediately following subframe is the subframe boundary symbol for neighboring subframes when the signal frame comprises a plurality of subframes and the Fast Fourier Transform (FFT) sizes of the neighboring subframes are different to each other.
2. The broadcast signal transmitter of claim 1 , wherein the at least one subframe has a fixed FFT size, fixed Guard Interval (GI) length and a fixed pilot pattern respectively and the preamble comprises FFT size information, GI information and pilot pattern information for each subframe.
3. The broadcast signal transmitter of claim 1 , wherein the preamble comprises subframe boundary symbol mode information and the subframe boundary symbol mode information indicates whether at least one of the first symbol of the subframe or the last symbol of the subframe is the subframe boundary symbol or not.
4. The broadcast signal transmitter of claim 1 , wherein a first symbol of a first subframe immediately following the preamble is the subframe boundary symbol when a FFT size of the preamble and a FFT size of the first subframe are different to each other.
5. The broadcast signal transmitter of claim 1 , wherein carrier separation of SPs for the subframe boundary symbol is determined as Dx of SP pattern for the data symbols of the subframe, the Dx being separation of pilot bearing carriers in a frequency direction.
6. A method for transmitting a broadcast signal, comprising:
input processing input data and outputting at least one Physical Layer Pipe (PLP) data;
error correction processing the PLP data;
generating a signal frame including the PLP data; and
Orthogonal Frequency Division Multiplexing (OFDM) modulating the signal frame and generating a transmission signal,
wherein the signal frame comprises a preamble and at least one subframe,
wherein the at least one subframe includes at least one subframe boundary symbol, the subframe boundary symbol being a first symbol or a last symbol of the at least one subframe and the subframe boundary symbol has a greater scattered pilot (SP) density than data symbols of the subframe, and
wherein at least one of a last symbol of an immediately preceding subframe or a first symbol of an immediately following subframe is the subframe boundary symbol for neighboring subframes when the signal frame comprises a plurality of subframes and the Fast Fourier Transform (FFT) sizes of the neighboring subframes are different to each other.
7. The method of claim 6 , wherein the at least one subframe has a fixed FFT size, fixed Guard Interval (GI) length and a fixed pilot pattern respectively and the preamble comprises FFT size information, GI information and pilot pattern information for each subframe.
8. The method of claim 6 , wherein the preamble comprises subframe boundary symbol mode information and the subframe boundary symbol mode information indicates whether at least one of the first symbol of the subframe or the last symbol of the subframe is the subframe boundary symbol or not.
9. The method of claim 6 , wherein a first symbol of a first subframe immediately following the preamble is the subframe boundary symbol when a FFT size of the preamble and a FFT size of the first subframe are different to each other.
10. The method of claim 6 , wherein carrier separation of SPs for the subframe boundary symbol is determined as Dx of SP pattern for the data symbols of the subframe, the Dx being separation of pilot bearing carriers in a frequency direction.