Modified Hamming Encoding for Shorter Run Lengths
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Solution Overview
Problem
In data communications, long run lengths in digital data sequences can cause clock recovery failures during synchronization, and standard Hamming codes often result in excessive run lengths due to insufficient transitions, leading to errors in error detection and correction.
Innovation Solution
A modified Hamming encoding method is applied to reduce the maximum run length by rearranging the coded data bits and using a combination of even and odd parity bits, specifically by moving the first 32 bits to the end of the sequence and computing parity bits using different parity types for the last two parity bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard Hamming codes are used for error detection and correction, then error correction capability is improved, but run length increases causing clock recovery failures
Solution Approach 1:
The patent segments the coded bit sequence by inserting transition bits (0 or 1) at specific positions to break up long runs of identical bits. This segmentation divides the continuous run length into smaller segments, ensuring the run length remains below the threshold that would cause clock recovery failures while preserving the error correction capability of the Hamming code structure.
Solution Approach 2:
The patent modifies the parameter of run length by dynamically adjusting the sequence of coded bits through rearrangement and insertion of transition bits. This changes the physical characteristic (run length) of the transmitted signal without altering the underlying error correction code structure, thereby resolving the contradiction between maintaining error correction capability and reducing run length.
2Reliability
If parity bits are intermingled among data bits in standard Hamming codes, then error detection capability is improved, but insufficient transitions occur leading to clock recovery failures
Solution Approach 1:
The patent performs preliminary action by pre-calculating and inserting transition bits at predetermined positions in the coded sequence before transmission. This preliminary arrangement ensures that sufficient transitions are present in the signal to enable successful clock recovery, while the underlying parity bit intermingling structure remains intact to maintain error detection capability.
Solution Approach 2:
The transition bits act as an intermediary element between the data bits and parity bits. These intermediary bits are inserted to provide the necessary signal transitions for clock recovery without interfering with the error detection and correction function of the parity bits, thus resolving the contradiction between error detection capability and transition frequency.
3Ease of operation
If the data stream contains long sequences of consecutive 1s or 0s, then data transmission simplicity is improved, but clock recovery fails due to insufficient transitions
Solution Approach 1:
The patent introduces dynamics into the data transmission process by adaptively inserting transition bits based on the content of the data stream. Rather than using a static encoding scheme, the system dynamically adjusts the transmitted sequence to ensure sufficient transitions are present, thereby maintaining clock recovery success while preserving the simplicity of the underlying data transmission format.
Data Source
AI summary
An encoder includes: an input configured to receive a plurality of data bits; a processor configured to encode the data bits utilizing a Hamming encoding operation to generate a plurality of coded bits; and an output configured to output the plurality of coded bits, wherein the processor is configured to reduce a maximum run length of the plurality of coded bits in comparison to coded bits corresponding to standard Hamming code.