Optical Framer Pseudo-Noise Insertion to Maintain Frame Lock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In optical communication networks, a loss of signal condition leads to an all zeros pattern that causes downstream network elements to lose frame, resulting in unnecessary protection switching and improper fault condition reporting, particularly in SONET/SDH and OTN systems.
Innovation Solution
A system and method that detect unacceptable data sequences, such as all zeros or low ones density, and insert a pseudo-noise pattern into the data stream to maintain framing, using detection circuitry, signal generator circuitry, and framing circuitry to replace the input data with pseudo-noise data, ensuring proper overhead framing and preventing loss of frame overhead and data communication channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an all zeros pattern is transmitted downstream during loss of signal condition, then the loss of signal is indicated to downstream elements, but frame loss occurs on all downstream network elements
Solution Approach 1:
The patent converts the harmful all-zeros pattern into a beneficial pseudo-random noise pattern that maintains frame synchronization. Instead of allowing the all-zeros pattern to cause frame loss, the system detects it and replaces it with a pseudo-random sequence that preserves the frame structure, thereby converting a harmful condition into a beneficial one that maintains downstream synchronization.
Solution Approach 2:
The patent introduces an intermediary pseudo-random noise pattern between the loss of signal condition and the downstream frame synchronization. This intermediary pattern acts as a mediator that prevents the direct transmission of the harmful all-zeros pattern while maintaining the necessary frame structure for downstream elements to remain synchronized.
2Reliability
If frame overhead is lost due to all zeros pattern, then downstream elements cannot maintain synchronization, but unnecessary protection switching is triggered
Solution Approach 1:
The patent applies preliminary anti-action by detecting the all-zeros pattern before it can cause frame loss and replacing it proactively. This preventive measure stops the chain reaction that would lead to frame overhead loss and unnecessary protection switching, thereby maintaining network availability and ensuring accurate fault reporting.
Solution Approach 2:
The patent implements feedback by continuously monitoring the incoming signal for all-zeros patterns and dynamically adjusting the transmitted pattern based on this feedback. When an all-zeros pattern is detected, the system responds by transmitting a pseudo-random noise pattern, creating a closed-loop control system that prevents frame loss and maintains synchronization.
3Reliability
If pseudo-noise pattern is inserted to maintain framing, then frame lock is maintained on downstream elements, but the original signal information is replaced
Solution Approach 1:
The patent extracts only the essential frame synchronization information from the original signal and transmits it in a protected pseudo-random noise pattern. By separating the frame structure from the data payload, the system maintains frame synchronization while acknowledging that the original signal data is replaced during loss of signal conditions.
Data Source
AI summary
The present disclosure provides systems and methods for inserting pseudo-noise in a data stream based on an unacceptable input data sequence in an optical network thereby preventing unnecessary loss of frame in SONET/SDH or Optical Transport Network (OTN) systems. The present disclosure includes a SONET/SDH or OTN framer, a transceiver, and a method for detecting an unacceptable data sequence or pattern and inserting a keep-alive or pseudo-noise sequence in the data sequence to maintaining framing on subsequent network elements, framers, transceivers, etc. For example, the present invention, upon receiving an unacceptable pattern of zeros or low ones density caused by a loss of signal condition or the like, may insert a pseudorandom noise pattern into the transmitted frame. This allows the downstream network element to continue a frame lock on the incoming signal, and thus keep the frame overhead and data communications channels from being lost.