Vehicle ECU App File Compression With CRC Header Integrity
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Solution Overview
Problem
The transfer of application files to vehicle control units is time-consuming and prone to failure due to long data transfer times and the need for integrity checks, which are compromised by compression, posing risks of corruption and damage.
Innovation Solution
The application file is separated into a header (AAH) and executable portion (Application), with the latter being compressed using a lossless algorithm, and the transfer is managed by a diagnostic tool to ensure compatibility and integrity checks are performed post-decompression, allowing for faster and safer file transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the application file is compressed to reduce transfer time, then the transfer speed is improved, but the integrity check capability is compromised
Solution Approach 1:
The application file is divided into two separate parts: a compressed executable portion and an uncompressed header containing the CRC integrity check value. This segmentation allows the bulk of the data to be compressed for faster transfer while the integrity verification data remains uncompressed and available for validation.
Solution Approach 2:
The CRC integrity check value is extracted from within the application file structure and placed in a separate uncompressed header. This extraction enables the compressed portion to be transferred efficiently while the extracted CRC value can be used independently for verification after decompression.
2Reliability
If the entire application file is transferred uncompressed to maintain integrity checks, then the reliability is improved, but the transfer time increases
Solution Approach 1:
The application file is segmented into a small uncompressed header containing only the CRC value and a large compressed executable portion. This segmentation strategy minimizes the amount of data that must remain uncompressed for integrity verification while maximizing the compression benefits for the bulk data transfer.
Solution Approach 2:
The compression state parameter is changed selectively applied to different portions of the application file. The executable portion is compressed to reduce transfer time, while the header portion containing the CRC remains uncompressed to maintain integrity check capability. This selective parameter change optimizes both speed and reliability.
3Productivity
If the application file is transferred faster by compressing, then the productivity is improved, but the risk of file corruption increases
Solution Approach 1:
The CRC integrity check value is prepared in advance and placed in an uncompressed header before the transfer begins. This preliminary action ensures that the verification mechanism is ready before the compressed data arrives, allowing immediate validation upon decompression without increasing corruption risk.
Solution Approach 2:
A feedback mechanism is implemented where the compressed application file is transferred quickly, decompressed, and then its integrity is verified against the pre-transferred CRC value. This feedback loop confirms data integrity after the fast transfer, mitigating the increased corruption risk associated with compression and decompression operations.
Data Source
AI summary
Method of generating an application file containing instructions for a vehicle ECU, the application file (Appfile) comprising a first header (AAH) comprising at least one field showing a CRC value calculated on the entire application file, an executable portion (Application), the method comprising a step (Step 1) of generating a modified application file (Appfile*) comprising said first header (AAH), unaltered, and the executable portion (Application*) compressed by means of a lossless compression algorithm.