OTU Frame Parity Layout for OTU/ODU Overhead Error Detection
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Solution Overview
Problem
In Optical Transport Networks (OTN), transmission errors in the OTU/ODU overhead cannot be detected using the existing BIP-8 method, as it only calculates parity for the OPU data area, excluding the overhead regions.
Innovation Solution
A transmission system with devices that calculate and insert bit interleaved parity of 8 bits (BIP-8) for specific areas including OTU/ODU overhead, allowing error detection by comparing calculated and extracted parity values, enabling error monitoring across OTU/ODU frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BIP-8 calculation is performed only on OPU data area as per G.709 standard, then the calculation complexity is reduced and processing is simplified, but transmission errors in OTU/ODU overhead cannot be detected
Solution Approach 1:
The patent applies local quality by performing BIP-8 calculation on different areas (OPU data area and OTU/ODU overhead) separately rather than uniformly across the entire frame. This allows error detection to be tailored to specific regions where it is most needed, improving reliability for overhead monitoring without unnecessarily complicating the entire calculation process.
Solution Approach 2:
The patent segments the OTU frame into distinct calculation areas: the OPU data area (columns 15-3824) and the OTU/ODU overhead area (columns 1-14). By dividing the calculation scope into separate segments, the system can independently monitor errors in each region, thereby enhancing overall error detection capability while maintaining manageable calculation complexity for each segment.
2Reliability
If BIP-8 calculation range is expanded to include OTU/ODU overhead, then error detection capability is improved, but calculation and processing complexity increases
Solution Approach 1:
The patent implements local quality by applying BIP-8 calculation specifically to the OTU/ODU overhead area (columns 1-14) in addition to the standard OPU data area. This targeted approach improves overhead error detection reliability without requiring complex recalculation of the entire frame, as each area is processed independently with appropriate parity insertion points.
Solution Approach 2:
The patent applies preliminary action by pre-defining the calculation ranges for BIP-8 in both the OPU data area and the OTU/ODU overhead area before transmission. The sending device prepares the parity values in advance for both regions, and the receiving device is pre-configured to extract and verify these parities, thereby improving overhead error detection without adding complex real-time processing requirements during transmission.
Data Source
AI summary
A transmission system carrying out sending and receiving of OTU frames has a first transmission device carrying out the sending of an OTU frame, and a second transmission device carrying out the receiving of the OTU frame. The first transmission device calculates BIP-8 for an objective calculation range preset in the OTU frame, inserts the calculation result into the OTU frame, and sends the same. The second transmission device calculates BIP-8 from the received OTU frame for the same objective calculation range as the first transmission device, compares the calculation result with the BIP-8 sent from the first transmission device, and detects any presence of transmission error. The calculation range is set in terms of one of an area including OPU only and an area at least including an arbitrary byte of OTU/ODU overhead.