Control Data Scrambling and Shortening for Lower OFDM PAPR
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Solution Overview
Problem
In digital broadcasting standards like DVB-T.2, the high Peak-to-Average Power Ratio (PAPR) of OFDM signals in T2 frames can lead to signal clipping in reception devices, degrading OFDM signal quality and complicating demodulation processing.
Innovation Solution
A data processing device and method that pads control data with dummy data, scrambles it, and performs BCH and LDPC error correction encoding, followed by shortening and puncturing, to adjust the data length and improve PAPR, allowing for easier processing in reception devices compliant with new standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If control data scrambling is performed to improve PAPR, then PAPR is improved, but reception device processing complexity increases
Solution Approach 1:
The patent applies preliminary action by performing scrambling on control data before error correction encoding (BCH and LDPC). This preliminary scrambling modifies the control data to improve PAPR characteristics before the data undergoes subsequent encoding and transmission processing, thereby reducing peak power issues at the source rather than dealing with them later in the reception chain.
Solution Approach 2:
The patent applies parameter changes by modifying the control data through scrambling operations that alter the statistical properties of the data sequence. This changes the amplitude distribution and peak characteristics of the control data, transforming it into a form with lower PAPR that is more suitable for OFDM transmission without requiring complex reception device modifications.
2Object-affected harmful factors
If control data scrambling is performed, then PAPR is improved, but demodulation processing difficulty increases
Solution Approach 1:
The scrambling is performed as a preliminary action before error correction encoding, preparing the control data for OFDM transmission by improving its PAPR characteristics. This preliminary modification ensures that the data is optimized for transmission before undergoing the standard encoding and modulation processes, making the overall demodulation process easier rather than more difficult.
Solution Approach 2:
The scrambled control data acts as an intermediary form that bridges the original control data and the final encoded transmission data. By introducing this intermediate scrambled version, the system achieves better PAPR characteristics while maintaining compatibility with standard error correction and demodulation processes, effectively mediating between PAPR requirements and processing simplicity.
3Object-affected harmful factors
If control data is padded with dummy data and scrambled, then PAPR is improved and data length is adjusted, but processing steps increase
Solution Approach 1:
The padding with dummy data and scrambling are performed as preliminary actions before error correction encoding. This sequence of preliminary operations prepares the control data in advance with optimal PAPR characteristics and correct length, allowing subsequent encoding and transmission to proceed efficiently without requiring additional corrective steps or reprocessing.
Solution Approach 2:
The patent merges multiple operations (padding with dummy data, scrambling, and error correction encoding) into a streamlined processing sequence. By combining these operations in a specific order and integrating them into the existing error correction framework, the system achieves PAPR improvement and data length adjustment without creating separate, inefficient processing paths.
Data Source
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AI summary
The present invention relates to a data processing device and a data processing method that can readily process control data having its PAPR improved. In a transmission device, a padder 21 pads control data necessary for demodulation with zeros as dummy data, and a scrambler 101 scrambles the padded control data (post-padding control data). A replacement unit 121 replaces scrambled dummy data in the scrambled post-padding control data with the dummy data, and a BCH encoder 22 and an LDPC encoder 23 perform BCH encoding and LDPC encoding as error correction encoding on the replacement data obtained through the replacement. A shortening unit 21 performs shortening by deleting the dummy data contained in the LDPC code and puncturing the parity bits of the LDPC code. The present invention can be applied in cases where control data is subjected to error correction encoding and is then transmitted, for example.