Erasure Coding for Partial Code Block Interruptions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication systems struggle to effectively recover from partial code block erasures caused by periodic disruptions, such as helicopter blade blockages, which result in signal distortion and attenuation, particularly in narrow-band channels with low symbol rates.
Innovation Solution
Implementing an outer erasure code that corrects for the expected erasure ratio by selecting an outer code block rate higher than the inner code block rate, allowing recovery of partially erased inner code blocks through a method that includes estimating the expected number of erasures based on periodic blockage duration and Clear Sky Energy per Symbol to Noise Power Spectral Density Ratio (Es/No), and encoding segments of the outer code block using inner and outer code rates to support a target Packet Error Ratio (PER).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error correction is used for periodic blockages, then communication reliability deteriorates under partial code block erasures, but increasing code block protection increases system complexity
Solution Approach 1:
The code block is segmented into multiple segments, each protected by independent error correction codes. This allows partial erasures to be corrected without requiring protection of the entire code block, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
Instead of applying full error correction protection to entire code blocks, the system applies partial protection only to affected segments. This excessive action on specific segments rather than uniform protection reduces complexity while achieving the required reliability for partial erasures.
2Reliability
If inner code block rate is lowered to reduce symbol loss, then error correction capability improves, but transmission efficiency deteriorates
Solution Approach 1:
Different code rates are applied to different segments based on their specific erasure conditions. Segments experiencing blockages use lower code rates for better correction, while unaffected segments maintain higher code rates for efficiency, achieving local optimization of both reliability and productivity.
Solution Approach 2:
The system dynamically changes code rate parameters based on detected erasure patterns and blockage conditions. This allows the error correction capability to be adjusted locally without uniformly reducing transmission efficiency across the entire communication channel.
3Reliability
If outer code block rate is increased to correct more erasures, then erasure correction capability improves, but inner code block protection deteriorates
Solution Approach 1:
The outer code block is segmented into multiple inner code blocks, each handling specific portions of the data. This segmentation allows the outer code to correct erasures at the segment level rather than requiring uniform protection, reducing information loss in unaffected segments while maintaining erasure correction capability.
Solution Approach 2:
The system introduces a hierarchical dimension with inner and outer coding layers. The outer code operates at a higher dimension to correct erasures across multiple inner blocks, while inner codes handle local protection, distributing the correction burden and reducing overall information loss.
Data Source
AI summary
A system and method for recovering from communication interruptions by a periodic blockage. This is achieved by selecting an inner code block rate that supports a Packet Error Ratio (PER) equal to or greater than a target PER during the blockage. An expected number of erasures is estimated and an outer code block rate capable of correcting an erasure ratio is chosen. The input is encoded using the outer code block rate to form an outer code block. One or more inner code blocks are formed by encoding segments of the outer code block using the inner code block rate. These inner code blocks are then transmitted. The count of inner code blocks is greater than 1, and the PER is a ratio of the expected number of erasures to the count of inner code blocks.