Control Data Scrambling for DVB-T2 PAPR Reduction

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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, especially when control data scrambling is applied.

Innovation Solution

A data processing device and method that scrambles control data to improve PAPR, involving techniques like BCH encoding, LDPC encoding, and scrambling, while ensuring compatibility with existing DVB-T.2 standards by appropriate padding and interleaving, and corresponding descrambling and restoration in reception devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If control data scrambling is performed to improve PAPR, then PAPR is improved, but device complexity increases due to additional scrambling and descrambling operations

Engineering Contradiction:
ImprovePAPRVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing scrambling on control data before encoding and transmission. The scrambler modifies the control data in advance to improve PAPR characteristics, and the corresponding descrambler restores the original data at the reception end, thereby resolving the contradiction between reliability improvement and device complexity increase.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If control data scrambling is performed, then PAPR is improved, but ease of operation deteriorates due to different processing requirements

Engineering Contradiction:
ImprovePAPRVSAvoidprocessing ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces an intermediary element (scrambler/descrambler pair) that facilitates PAPR improvement while maintaining processing ease. The scrambler acts as a mediator that transforms control data into a form with better PAPR characteristics, and the descrambler mediates the restoration process, allowing the system to achieve both improved reliability and maintained ease of operation through standardized intermediary components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4002700B1Device and method for removing dummy data and parity bits of concatenated BCH/LDPC code
Publication Date: 2024.06.12 SATURN LICENSING LLC
  • EP4002700B1 patent drawingFigure 1
  • EP4002700B1 patent drawingFigure 2
  • EP4002700B1 patent drawingFigure 3

AI summary

The present invention relates to a data processing device and a data processing method for reducing peak to average power ratio (PAPR) and for limiting the modification and complexity necessary for achieving the PAPR reduction in a classical DVB-T2 receiver. Control data are first scrambled. Then the scrambled control data are padded with dummy bits. The scrambled data and the padding bits undergo concatenated coding, the concatenated coding consisting first of Bose-Chaudhuri-Hocquenghem, BCH, encoding and then of Low Density Parity Check, LDPC, encoding. Prior to transmission and in order to limit the amount of transmitted bits, parity bits of the LDPC code are punctured and dummy data are removed from the transmitted data. A frame is built containing the punctured LDPC and BCH coded scrambled control data without padding bits, a preamble in the frame including a symbol including information that the frame contains the punctured LDPC and BCH coded scrambled control data without padding bits, and the frame is multiplexed in a DVB-T2 signal.