DVB-T2 Receiving Apparatus Early PLP Decoding via Offset Feedback
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Solution Overview
Problem
Existing receiving apparatuses for DVB-T2 OFDM signals face challenges in early decoding of the intended PLP due to the time-consuming process of estimating coarse carrier offsets, which delays the correct demodulation of parameters and subsequent data decoding.
Innovation Solution
A receiving apparatus and method that includes preamble analysis, offset detection for fine and coarse offsets, carrier frequency correction, and control signal management to facilitate early decoding of the PLP by determining the completion of coarse offset detection and feeding back fine offset corrections for efficient carrier frequency correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiving apparatus executes the complete coarse offset detection process before PLP decoding, then the carrier frequency correction accuracy is improved, but the decoding time is increased
Solution Approach 1:
The patent applies preliminary action by detecting the fine offset using the correlation method before completing the full coarse offset detection process. The fine offset detection is performed in advance on the received preamble signal to obtain an initial correction value, which is then used to adjust the carrier frequency before PLP decoding begins. This allows partial frequency correction to be achieved beforehand, reducing the time required for complete offset detection while maintaining sufficient accuracy for early decoding.
Solution Approach 2:
The patent segments the carrier frequency correction process into two distinct stages: fine offset detection using correlation method and coarse offset detection using frequency search method. The fine offset detection is performed first on the preamble signal to achieve initial frequency alignment, followed by coarse offset detection to refine the correction. This segmentation allows the system to perform partial correction earlier, enabling PLP decoding to start before the complete coarse offset detection is finished, thus resolving the contradiction between accuracy and time.
2Measurement precision
If the receiving apparatus performs both fine offset and coarse offset detection, then the demodulation accuracy is improved, but the processing complexity is increased
Solution Approach 1:
The patent divides the offset detection into two separate functional modules: a fine offset detection unit that uses correlation method on the preamble signal, and a coarse offset detection unit that uses frequency search method. Each module is independently configured with its own processing logic and computational requirements. This segmentation allows the system to perform both types of detection without requiring a single complex algorithm, thereby improving demodulation accuracy while managing processing complexity through modular design.
Solution Approach 2:
The patent performs fine offset detection as a preliminary step before coarse offset detection. The fine offset detection using correlation method provides an initial accurate correction that simplifies the subsequent coarse offset detection process. By performing the correlation-based fine detection first, the system reduces the search space for the coarse frequency search, thereby improving overall demodulation accuracy while actually reducing the total processing complexity compared to performing only a broad frequency search.
Data Source
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AI summary
Disclosed herein is a receiving apparatus including a preamble analyzer configured to receive a frame of DVB-T2 made up of an OFDM signal and analyze a preamble contained in the received frame; an offset detector configured to detect a fine offset and a coarse offset on the basis of the analyzed preamble; a carrier frequency corrector configured to execute carrier frequency correction on an OFDM time domain signal obtained by quadrature demodulation on the basis of the detected fine offset and the detected coarse offset; a determiner configured to determine whether the detection of the coarse offset has been completed; and a control signal outputter configured, if the detection of the coarse offset is determined to be completed, to output a control signal for feeding back the fine offset detected on the basis of an OFDM frequency domain signal obtained by FFT computation to the carrier frequency corrector.