Data processing apparatus and data processing method
The present technology relates to a data processing apparatus and a data processing method which can suppress the influence of multipath propagation and the Doppler shift. A data processing apparatus includes a processing unit which performs modulation processing on a physical layer frame including a preamble, which includes a modulation parameter, and one or more subframes, which include data, in which any modulation parameter can be set for each of the subframes, and the subframes are arranged in the physical layer frame collectively by subframe groups which are collections of the subframes with FFT sizes, which are same, when IFFT operation is performed on symbols included in the physical layer frame. The present technology can be applied to, for example, data transmission compliant to a broadcast standard such as ATSC 3.0.
1. A data processing apparatus comprising:
circuitry configured to perform modulation processing on a physical layer frame including a preamble and plural subframes, wherein different fast Fourier transform (FFT) sizes are respectively set for at least two of the subframes, and
the subframes are arranged in the physical layer frame in contiguous subframe groups, each subframe group of the contiguous subframe groups including all subframes of the physical layer frame with a same FFT size, at least one subframe group of the contiguous subframe groups including plural subframes with the same FFT size, when inverse fast Fourier transform (IFFT) operation is performed on symbols included in the physical layer frame, and
an FFT size of the preamble of the physical layer frame is less than or equal to an FFT size of subframes in a subframe group immediately following the preamble.
2. The data processing apparatus according to claim 1 , wherein the subframe groups are disposed in ascending order of FFT sizes in the physical layer frame.
3. The data processing apparatus according to claim 1 , wherein the FFT sizes of the subframes represent numbers of samples to be subjected to one IFFT operation.
4. The data processing apparatus according to claim 1 , wherein a modulation method of a signal processed in the modulation processing is orthogonal frequency division multiplexing (OFDM), and
the physical layer frame includes a plurality of OFDM symbols.
5. The data processing apparatus according to claim 1 , wherein a distribution of pilot signals within each subframe in the physical layer frame is equal to in density or less dense than a distribution of pilot signals in any preceding subframe in the physical layer frame.
6. A data processing method of a data processing apparatus, the method comprising:
performing modulation processing on a physical layer frame including a preamble and plural subframes,
wherein different fast Fourier transforms (FFT) sizes are respectively set for at least two of the subframes,
the subframes are arranged in the physical layer frame in contiguous subframe groups, each subframe group of the contiguous subframe groups including all subframes of the physical layer frame with a same FFT size at least one subframe group of the contiguous subframe groups including plural subframes with the same FFT size, when IFFT operation is performed on symbols included in the physical layer frame, and
an FFT size of the preamble of the physical layer frame is less than or equal to an FFT size of subframes in a subframe group immediately following the preamble.
7. The data processing method according to claim 6 , wherein a distribution of pilot signals within each subframe in the physical layer frame is equal to in density or less dense than a distribution of pilot signals in any preceding subframe in the physical layer frame.
8. A data processing apparatus comprising:
circuitry configured to perfoiui demodulation processing on a physical layer frame including a preamble and plural subframes,
wherein different fast Fourier transform (FFT) sizes are respectively set for at least two of the subframes,
the subframes are arranged in the physical layer frame in contiguous subframe groups, each subframe group of the contiguous subframe groups including all subframes of the physical layer frame with a same FFT size, at least one subframe group of the contiguous subframe groups including plural subframes with the same FFT size, when fast Fourier transform (FFT) operation is performed on symbols included in the physical layer frame, and
an FFT size of the preamble of the physical layer frame is less than or equal to an FFT size of subframes in a subframe group immediately following the preamble.
9. The data processing apparatus according to claim 8 , wherein the subframe groups are disposed in ascending order of FFT sizes in the physical layer frame.
10. The data processing apparatus according to claim 8 , wherein the FFT sizes of the subframes represent numbers of samples to be subjected to one FFT operation.
11. The data processing apparatus according to claim 8 , wherein a modulation method of a signal processed in the demodulation processing is OFDM, and
the physical layer frame includes a plurality of OFDM symbols.
12. The data processing apparatus according to claim 8 , wherein a distribution of pilot signals within each subframe in the physical layer frame is equal to in density or less dense than a distribution of pilot signals in any preceding subframe in the physical layer frame.
13. A data processing method of a data processing apparatus, the method comprising:
performing demodulation processing on a physical layer frame including a preamble and plural subframes, wherein different fast Fourier transform (FFT) sizes are respectively set for at least two of the subframes,
the subframes are arranged in the physical layer frame in contiguous subframe groups, each subframe group of the contiguous subframe groups including all subframes of the physical layer frame with a same FFT size, at least one subframe group of the contiguous subframe groups including plural subframes with the same FFT size, when FFT operation is performed on symbols included in the physical layer frame, and
an FFT size of the preamble of the physical layer frame is less than or equal to an FFT size of subframes in a subframe group immediately fallowing the preamble.
14. The data processing method according to claim 13 , wherein a distribution of pilot signals within each subframe in the physical layer frame is equal to in density or less dense than a distribution of pilot signals in any preceding subframe in the physical layer frame.