Iterative FEC Decoder Tuning for Optical Link Error Correction
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Solution Overview
Problem
Optical communication systems face challenges in accurately determining the optimal number of iterations for iterative decoders to provide sufficient error correction, as this number varies with different optical links and error conditions, leading to inefficiencies in data transmission.
Innovation Solution
A method is introduced where errored bits are intentionally inserted into a data stream, transmitted over an optical link, and decoded using an iterative decoder. The number of iterations required to correct these bits is determined, allowing for the calculation of the necessary iterations to correct additional errors caused by the link, thereby optimizing the decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of iterations is increased to correct more errors, then error correction capability is improved, but decoding time increases
Solution Approach 1:
The patent applies dynamics by making the number of iterations adjustable and adaptive rather than fixed. The system dynamically determines the optimal number of iterations based on measured channel conditions and error rates, allowing it to increase iterations when errors are high and decrease them when errors are low, thus resolving the contradiction between error correction capability and decoding time.
Solution Approach 2:
The patent changes the parameter of iteration count based on measured system conditions. By monitoring bit error rates and channel characteristics, the system adjusts the iteration parameter to optimize performance, achieving sufficient error correction with minimal iterations under varying channel conditions.
2Productivity
If the number of iterations is decreased to increase decoding speed, then productivity is improved, but error correction capability deteriorates
Solution Approach 1:
The system dynamically adapts the iteration count to channel conditions, using fewer iterations when the channel is good (high signal quality) and more iterations when the channel is poor (low signal quality). This dynamic adjustment maintains high decoding speed while ensuring sufficient error correction capability under varying conditions.
Solution Approach 2:
The iteration parameter is changed based on measured error rates and channel characteristics. The system monitors performance metrics and adjusts the iteration parameter accordingly, achieving high productivity when possible while maintaining adequate error correction when needed.
3Device complexity
If a fixed number of iterations is used for all optical links, then device complexity is reduced, but adaptability deteriorates
Solution Approach 1:
The patent changes operational parameters (iteration count) based on measured channel characteristics without changing the physical structure of the decoder. This allows the same decoder hardware to adapt to different optical links by adjusting software-controlled parameters, maintaining low device complexity while achieving high adaptability.
Solution Approach 2:
The system introduces dynamic parameter adjustment capability that allows the decoder to adapt to different optical link conditions. By making the iteration count configurable and adaptive rather than fixed, the system achieves versatility across different links without increasing fundamental decoder complexity.
Data Source
AI summary
Consistent the present disclosure, errored bits are inserted into a data stream, which is carried by an optical signal. The optical signal is transmitted over an optical link that may induce additional errors, i.e., add additional errored bits to the data stream. At the receive end, the optical signal is converted into a corresponding electrical signal that carries the data stream. The data stream is subject to forward error correction (FEC) decoding with an iterative decoder, for example. The iterative decoder decodes the data stream over a number of iterations until both the inserted errored bits and the additional errored bits are corrected. Since the number of inserted bits is known, the number of iterations required to correct the inserted bits is also known (“first iterations”). Accordingly, the number of iterations required to correct the additional errored bits caused by transmission over the optical link may be determined based on the total number of iterations performed and the number of the first iterations.