CRC Majority Voting for Encrypted Retransmission Error Correction
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Solution Overview
Problem
Existing CRC-EC techniques are suboptimal for encrypted bit-streams and do not effectively handle bit errors in wireless communication systems, particularly in scenarios involving retransmissions and encrypted data, leading to significant audio quality degradation.
Innovation Solution
A majority vote-based CRC-EC scheme that corrects bit errors by comparing CRC syndromes across multiple transmissions, even when encrypted payloads are not directly accessible to firmware, by appending CRC parity bits to decrypted streams and using extended bit-streams for error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing CRC-EC techniques are used for encrypted bit-streams, then error detection capability is maintained, but bit error correction efficiency deteriorates significantly
Solution Approach 1:
The patent segments the correction process into two distinct phases: (1) CRC-based error detection to identify potential error locations, and (2) majority vote-based error correction to actually correct the errors. This segmentation allows each phase to optimize for its specific function, resolving the contradiction between maintaining detection capability and improving correction efficiency.
Solution Approach 2:
The patent introduces an intermediary majority vote mechanism that operates on decrypted portions of the bit-stream. This intermediary layer enables effective error correction without requiring direct access to the encrypted payload, thus maintaining both detection capability and correction efficiency for encrypted streams.
2Adaptability or versatility
If CRC-EC is applied to encrypted bit-streams without direct payload access, then security is maintained, but correction accuracy deteriorates
Solution Approach 1:
The patent applies partial decryption or error correction to specific portions of the bit-stream (such as header fields or selected payload sections) rather than requiring complete decryption. This partial action maintains security for the encrypted portions while achieving sufficient correction accuracy for the accessible portions.
Solution Approach 2:
The patent replaces the traditional mechanical approach of full decryption with a cryptographic substitution approach, where error correction is performed on encrypted or partially encrypted data using mathematical operations that work directly on the ciphertext, eliminating the need to expose plaintext.
3Reliability
If multiple retransmissions are used for error correction, then bit error correction capability is improved, but computational complexity increases
Solution Approach 1:
The patent performs preliminary error detection using CRC checks on received transmissions before attempting correction. This preliminary action identifies which transmissions contain errors and guides the subsequent correction process, reducing unnecessary computational operations and lowering overall complexity while maintaining correction capability.
Solution Approach 2:
The patent dynamically adjusts correction parameters such as the number of retransmissions to attempt, the threshold for majority voting, and the portions of data to decrypt based on observed error rates and computational resource availability. This parameter adaptation optimizes the balance between correction capability and computational complexity.
Data Source
AI summary
An apparatus may receive a first copy, a second copy and a third copy of data including a cyclic redundancy check (CRC) code, determine that a number of one or more bit positions, at each of which at least two of the first copy, the second copy or the third copy have bit values different from each other, is greater than a threshold value, divide the one or more bit positions into a first set of bit positions corresponding to the threshold value and remaining bit positions, determine, among the remaining bit positions, a second set of bit positions at each of which both the second copy and the third copy have a same bit value different from a bit value at a corresponding bit position of the first copy, and correct, using the second set of bit positions, an error in the first copy.