Viterbi Decoder Polarity Estimation for Stable E8-VSB Reception
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Solution Overview
Problem
The existing ATSC 8VSB transmission method lacks stability in receiving video signals, particularly due to content-specific data, and there is a need for enhanced reception standards that do not compromise conventional signal reception, while also supporting new services.
Innovation Solution
An enhanced 8 vestigial sideband (E8-VSB) Viterbi decoder is developed, which includes a tuner, IF mixer, demodulator, equalizer, and Viterbi decoder with ACS units, polarity estimation, and decision selection to decode both enhanced and main symbols, ensuring stable reception of digital broadcast signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ATSC 8VSB transmission method is used, then basic video signal reception is maintained, but reception stability deteriorates due to content-specific data
Solution Approach 1:
The patent segments the received signal into enhanced symbols and main symbols, processing them through different decoding paths. The Viterbi decoder is divided into multiple ACS units that independently process different symbol types, allowing stable reception of conventional signals while enabling support for enhanced content-specific data services.
Solution Approach 2:
The Viterbi decoder is designed with multi-functionality to handle both conventional ATSC 8VSB signals and enhanced E8-VSB signals with content-specific data. By incorporating multiple ACS units that can process different symbol types (enhanced and main symbols), the system achieves universal compatibility without compromising reception stability.
2Adaptability or versatility
If enhanced reception standards are added, then new services are enabled, but compatibility with conventional signal reception may be compromised
Solution Approach 1:
The patent segments the decoding process into separate ACS units: a first ACS unit processes enhanced symbols for new services, while a second ACS unit processes main symbols for conventional signal reception. This segmentation ensures that enhanced services can be added without interfering with the stability of conventional signal reception.
Solution Approach 2:
Different parts of the Viterbi decoder are assigned different functions based on local quality principles. The first ACS unit is optimized for enhanced symbols with content-specific data, while the second ACS unit maintains the original processing characteristics for main symbols, ensuring each section operates with optimal performance for its specific purpose.
3Measurement precision
If dual ACS units are used to process enhanced and main symbols, then decoding accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges the functionality of separate enhanced symbol processing and main symbol processing into a single integrated Viterbi decoder structure. By combining multiple ACS units within one decoder framework and sharing common resources such as the polarity inversion estimator and decision selection unit, the system achieves improved decoding accuracy while minimizing the increase in device complexity.
Solution Approach 2:
The Viterbi decoder is designed as a universal multi-functional unit that can process both enhanced and main symbols. The shared components (polarity inversion estimator, decision selection unit) perform multiple functions, reducing overall device complexity while maintaining the ability to accurately decode different symbol types through the specialized ACS units.
Data Source
AI summary
An enhanced VSB receiver includes a tuner which tunes an RF signal and converts it into an IF signal, an IF mixer which converts the IF signal into a baseband signal, and a demodulator which demodulates the baseband signal signal into a VSB signal. The enhanced VSB receiver further includes a map recovery unit which recovers VSB map information of the VSB signal, an enhanced equalizer for compensating channel distortion of the VSB signal and outputting an equalized symbol, and an enhanced Viterbit decoder for estimating whether polarity inversion occurred during a symbol period of the equalized symbol and Viterbi-decoding the equalized symbol based on the polarity estimation.