OTN Client Signal Mapping with Code Blocks for Low-Rate Traffic

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Solution Overview

Problem

Existing optical transport network (OTN) technologies suffer from significant bandwidth waste when transmitting low-rate signals due to a minimum slot granularity of 1.25 G, leading to inefficiencies in carrying traffic lower than 1.25 G, such as fast ethernet (FE) and synchronous transfer module-1 (STM-1) signals.

Innovation Solution

A method involving mapping client signals into predetermined containers, such as optical service unit (OSU) or ODU containers, and dividing the payload area of optical transport network frames into code blocks using a sigma-delta algorithm to insert idle code blocks for rate adjustment, ensuring efficient bandwidth utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the minimum slot granularity of 1.25 G is used for signal mapping, then the OTN standard compliance is improved, but the bandwidth utilization deteriorates when carrying low-rate signals

Engineering Contradiction:
ImproveOTN standard complianceVSAvoidbandwidth waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the fixed 1.25G slot into multiple variable-sized sub-slots (e.g., 66b code blocks of approximately 200Mb each). This allows low-rate signals to occupy only the necessary portion of the slot, reducing bandwidth waste while maintaining OTN standard compliance through proper framing and overhead structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic slot allocation where the number and size of sub-slots within a 1.25G slot can be adjusted based on the actual signal rate being carried. This dynamic configuration allows efficient bandwidth utilization for varying signal rates while preserving the fixed 1.25G slot structure required by OTN standards.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If fixed-size slots are used for mapping, then the device complexity is reduced, but the adaptability to different signal rates deteriorates

Engineering Contradiction:
Improvemapping structure simplicityVSAvoidsignal rate adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides each fixed 1.25G slot into multiple standardized 66b code blocks that can be dynamically allocated. This segmentation maintains the simplicity of fixed-size block structures while enabling flexible adaptation to different signal rates by varying the number of blocks assigned to each signal.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal mapping structure where the same 1.25G slot format and 66b code block structure can carry signals of various rates (from 2M E1 to 10G Ethernet). The multi-functionality is achieved through flexible allocation of code blocks within the standardized slot, eliminating the need for different mapping structures for different signal types.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3920438B1Method, device and system for customer business transfer, and computer readable storage medium
Publication Date: 2026.02.04 ZTE CORP
  • EP3920438B1 patent drawingFigure 1~2
  • EP3920438B1 patent drawingFigure 3~4
  • EP3920438B1 patent drawingFigure 5~6

AI summary

Provided are a client signal transmission method, apparatus and system and a computer-readable storage medium. The method includes mapping a client signal into a predetermined container corresponding to the client signal; mapping the predetermined container into the corresponding number of first code blocks in a payload area of an optical transport network frame and inserting special idle code blocks during the mapping for rate compensation, where the first code blocks are obtained by dividing the payload area of the optical transport network frame; and sending the optical transport network frame carrying the predetermined container and configuration information of the predetermined container.