Parallel Error-Correction Modules for Burst Noise Decoding
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Solution Overview
Problem
In communication systems, especially terrestrial broadcasting, severe fading and interference cause burst noise that can overwhelm existing error correction capabilities, leading to error propagation and insufficient correction of errors in concatenated coding systems, particularly when exact erasure marking is uncertain and SNR is low.
Innovation Solution
An apparatus and method that utilize two error-correcting modules functioning in parallel: an error decoder and an error-erasure decoder, with an unreliable-location determining module to generate an indication signal, allowing for enhanced error correction by selecting between candidate signals based on error and erasure correction capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an RS error decoder with t-error correction capability is used as the outer decoder, then the system can correct up to t errors, but it cannot sufficiently correct burst errors exceeding t errors caused by severe fading or interference
Solution Approach 1:
The patent divides the error correction task into two segments: an RS error decoder that corrects up to t errors, and an RS error-erasure decoder that handles additional errors when erasure locations are provided. This segmentation allows the system to address both small error scenarios and severe burst error scenarios by selecting the appropriate decoder path.
Solution Approach 2:
The patent performs preliminary identification of unreliable symbol locations before the error correction process. By marking erasure locations in advance based on reliability metrics from the inner decoder or channel conditions, the system prepares the error-erasure decoder with location information, enabling it to correct more errors than the standard RS decoder alone.
2Reliability
If an RS error-erasure decoder is used to correct more than t errors, then the correction capability increases, but the system requires accurate erasure location marking which is difficult to achieve exactly and efficiently
Solution Approach 1:
The patent applies partial erasure marking by identifying only the most unreliable symbol locations rather than attempting to mark all possible error locations. This partial action approach provides the error-erasure decoder with sufficient information to correct errors without requiring perfect precision in marking every unreliable location, thus balancing complexity and performance.
Solution Approach 2:
The patent introduces an intermediate unreliable-location determining module that acts as a mediator between the received signal and the error-erasure decoder. This module generates erasure indicators based on reliability metrics, providing the decoder with location information without requiring the decoder itself to perform complex analysis, thus separating the measurement function from the correction function.
3Productivity
If the inner decoder uses algorithms like Viterbi decoding, then it can correct errors in real-time, but it may cause error propagation that deteriorates overall error correction performance
Solution Approach 1:
The patent implements a feedback mechanism where the unreliable-location determining module uses reliability metrics from the inner decoding process to identify erasure locations. This feedback loop allows the system to detect and mark error-prone locations that resulted from inner decoding, preventing error propagation from affecting the outer decoding stage and enabling the error-erasure decoder to focus on correcting marked locations.
Data Source
AI summary
An apparatus for error-correcting an input signal to generate an output signal. The apparatus includes an unreliable-location determining module for determining unreliable-locations of the input signal and generating an indication signal accordingly, a first error-correcting module for error-correcting the input signal to generate a first candidate signal, a second error-correcting module coupled to the unreliable-location determining module for error-correcting the input signal with reference to the indication signal to generate a second candidate signal, and a selecting module coupled to the first and second error-correcting modules for selecting one of the first and second candidate signals to be the output signal.