Turbo Code Decoding With Early CRC Error Detection
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Solution Overview
Problem
Turbo code-based communication systems lack an effective error detection mechanism, leading to prolonged decoding latency due to the need for multiple iterations to achieve an acceptable bit error rate.
Innovation Solution
Incorporating an error detection indicator and cyclic redundancy check (CRC) codes into the Turbo code encoding scheme to determine error occurrence during transmission, allowing for early termination of decoding or retransmission requests, thereby reducing decoding latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple decoding iterations are performed to achieve acceptable bit error rate, then reliability is improved, but decoding latency increases
Solution Approach 1:
The patent applies preliminary action by performing error detection (using CRC or indicator evaluation) before completing multiple decoding iterations. This allows the system to detect errors early in the decoding process and terminate further iterations, preventing unnecessary time consumption while maintaining reliability through early error identification.
Solution Approach 2:
The patent implements feedback by using error detection results (CRC check or indicator evaluation) to control the decoding iteration process. The error detection feedback determines whether to continue or terminate decoding iterations, enabling the system to adapt the number of iterations based on actual error conditions rather than always performing fixed multiple iterations.
2Loss of time
If error detection mechanism is added to Turbo code system, then decoding latency is reduced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by separating the error detection function from the main Turbo decoding process. The error detection mechanism (CRC or indicator evaluation) operates as an independent module that can be applied to decoded outputs at specific iteration points, allowing the system to reduce latency without significantly increasing the complexity of the core Turbo decoder.
Solution Approach 2:
The patent uses an intermediary error detection mechanism (CRC code or indicator) that bridges the Turbo decoding process and the final error determination. This intermediary layer provides a simple check that doesn't require complex modifications to the Turbo decoder itself, thus reducing latency while minimizing the increase in overall system complexity.
Data Source
AI summary
A method and a decoder for receiving a message encoded in Turbo Codes and modulated for transmission as an analog signal includes: (a) demodulating the analog signal to recover the Turbo Codes; and (b) decoding the Turbo Codes to recover the message using an iterative Turbo Code decoder, wherein the decoding includes performing an error detection after a predetermined number of iterations of the Turbo Code decoder to determine whether or not an error has occurred during the transmission. The predetermined number of iterations may be, for example, two. Depending on the result of the error detection, the decoding may stop, a request for retransmission of the message may be sent, or further iterations of decoding in the Turbo Code decoder may be carried out.