OTN Transmission Circuit Burst Error Correction via Superframe Interleaving
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Solution Overview
Problem
Current optical communication systems face challenges in error correction for burst errors, particularly at higher transfer speeds, as the time slot per frame becomes shorter, making it difficult to disperse and correct errors within the OTU4 frame, leading to increased processing loads when handling multiframe signals.
Innovation Solution
A transmission circuit and reception circuit that detect and rearrange the sequence of OTN frame signals within a multiframe unit, generating quasi-OTN frame signals with a Multiframe Alignment Signal (MFAS), allowing for error correction without increasing processing load by dispersing errors across frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction code is generated for each subframe with fixed size, then error correction can be performed within subframe, but with increase in transfer speed, time slot per frame becomes short and errors cannot be dispersed effectively
Solution Approach 1:
The patent combines multiple OTN frames (e.g., 4 frames) into a superframe structure, merging their error correction capabilities. The FEC encoder generates a single error correction code that covers all constituent frames within the superframe, allowing errors to be dispersed across the combined structure rather than being confined to individual frames. This resolves the contradiction by maintaining error correction effectiveness even as individual frame time slots become shorter at higher speeds.
Solution Approach 2:
The patent extends the error correction dimension from the frame level to the superframe level. By organizing multiple frames hierarchically within a superframe and applying FEC at this higher dimension, the system achieves error dispersion across a larger temporal and structural scope. This dimensional extension allows the system to maintain reliability at higher transfer speeds where individual frame durations are insufficient for effective error dispersion.
2Reliability
If interleaving is performed continuously across multiple frames to disperse errors, then error correction effectiveness improves, but processing load increases remarkably
Solution Approach 1:
The patent segments the error correction process by applying FEC independently to each superframe unit rather than continuously across all frames. This segmentation allows the system to process errors in manageable chunks, reducing the continuous processing load while maintaining effective error dispersion within each superframe. The superframe acts as an independent processing unit, breaking down the complex task of multi-frame error correction into smaller, more manageable segments.
Solution Approach 2:
The patent performs preliminary organization of frames into superframe structures before error correction is applied. By pre-defining the superframe boundaries and constituent frames, the system prepares the data structure in advance, allowing error correction to be applied efficiently to the predetermined unit. This preliminary structuring reduces the processing complexity during actual error correction operations, as the system doesn't need to dynamically determine processing boundaries.
3Productivity
If OTN frame time slot is shortened due to increased transfer speed, then data transmission capacity increases, but time available for error dispersion and correction becomes insufficient
Solution Approach 1:
The patent merges multiple short-duration frames into a longer superframe structure, effectively combining the time resources of individual frames. This merging creates a extended time window for error dispersion and correction, allowing the system to maintain adequate error correction capability even when individual frame durations are shortened due to increased transfer speeds. The superframe's total duration provides sufficient time for effective FEC operation.
Solution Approach 2:
The patent shifts the error correction timescale from the individual frame dimension to the superframe dimension. By operating at this higher temporal dimension, the system achieves effective error dispersion over a longer cumulative time period, compensating for the shortened individual frame slots. This dimensional shift allows high-speed transmission to proceed while maintaining adequate error correction time at the superframe level.
Data Source
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AI summary
Provided is a transmission circuit with which it is possible to facilitate error correction of burst errors without increasing the processing load in multiframes configured from a plurality of OTN frame signals. This transmission circuit is provided with: a transmission-side signal recognition unit for detecting MFAS and recognizing the order of N number of OTN frame signals; an intra-multiframe sequence conversion unit for converting the sequence of data signals inside the multiframe in response to the recognized order; a transmission-side rearranging unit for consolidating the sequentially converted data signals into lengths equal to those of the OTN frame signals and creating N number of quasi-OTN frame signals; and a transmission unit for transmitting the multiframes configured from the N number of quasi-OTN frame signals.