Sectionalizing Adaptive Equalizer for VSB Signal Processing
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Solution Overview
Problem
ATSC 8-VSB digital TV broadcasting systems face challenges in estimating time-varying channels at high speeds, particularly in mobile environments, limiting their reception performance.
Innovation Solution
The system divides the VSB signal into sections, recursively adaptively equalizes each section using a recursive adaptive equalizer, and constructs a bit stream by initializing subsequent sections with state values from previous equalizations, including path metrics and traceback information, while disregarding overlapping symbol periods to enhance channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a receiver uses traditional equalization methods for ATSC 8-VSB signals, then the system is simple to implement, but it cannot estimate time-varying channels at high speeds in mobile environments
Solution Approach 1:
The patent divides the continuous signal into multiple sections and processes each section independently through recursive adaptive equalization. This segmentation allows the equalizer to handle time-varying channels more effectively by adapting to changes within each section, thereby improving channel estimation accuracy without requiring the entire signal to be processed simultaneously with complex computations.
Solution Approach 2:
The patent uses preliminary equalization of previous sections to initialize the equalizer state for current sections. By performing equalization in advance on prior sections and storing their results as initial conditions, the system reduces the computational burden for current section equalization while maintaining high estimation accuracy through the accumulated knowledge from previous processing stages.
2Reliability
If the equalizer adapts parameters at high speed to overcome multi-path effects, then mobile reception performance improves, but the receiver cannot accurately estimate time-varying channels
Solution Approach 1:
The patent implements recursive adaptive equalization where the equalizer continuously adjusts its parameters based on feedback from the equalized output. This feedback mechanism allows the equalizer to adapt to time-varying channel conditions in real-time, improving both mobile reception reliability and channel estimation accuracy by continuously refining its parameters based on actual signal characteristics.
Solution Approach 2:
The patent employs dynamic equalization parameters that change adaptively based on the processing section and channel conditions. By making the equalizer parameters dynamic rather than static, the system can optimize performance for each specific section while maintaining the ability to track time-varying channel characteristics, thus improving both reliability and estimation accuracy simultaneously.
3Productivity
If the system processes entire symbol sequences with traditional equalization, then processing is simple, but it cannot converge equalizer coefficients to optimal values quickly enough
Solution Approach 1:
The patent segments the symbol sequence into smaller sections and processes each section independently through recursive adaptive equalization. This segmentation enables faster convergence of equalizer coefficients because each section can be equalized quickly without waiting for the entire sequence to be processed, thereby improving productivity while the modular structure keeps the complexity manageable.
Solution Approach 2:
The patent performs preliminary equalization on previous sections and stores their results as initial conditions for subsequent sections. This preliminary action significantly reduces the computation time required for each new section, enabling rapid convergence of equalizer coefficients across the entire sequence without requiring complex processing of the entire sequence at once.
Data Source
AI summary
A symbol sequence corresponding to a vestigial sideband (VSB) signal is divided into a plurality of sections, respective ones of which correspond to respective time periods. Individual ones of the sections are recursively adaptively equalized to produce respective equalized sections. A bit stream is constructed from the equalized sections.