Optical Receiver BER Feedback Using Frame Alignment Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical communication systems face high bit error rates during system start-up, exceeding the error correcting capability of forward error correction (FEC) codes, making it challenging to ensure reliable data transmission.
Innovation Solution
A method and apparatus that convert optical signals to electrical signals, identify frame alignment signals, determine bit error rates, and adjust parameters based on these rates to reduce bit error rates, enabling effective FEC decoding by controlling optical or electrical components in the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system operates during start-up, then the optical components are initializing, but the bit error rate exceeds the FEC correction threshold
Solution Approach 1:
The system performs preliminary actions by detecting the frame alignment signal before normal data processing begins. This early detection allows the system to identify the start of frames and calculate bit error rates during the initialization phase, enabling proactive adjustment of optical parameters before errors accumulate beyond correction capability
Solution Approach 2:
The system implements feedback by continuously monitoring the bit error rate calculated from frame alignment signals and using this information to adjust optical component parameters. The feedback loop compares the measured BER against the FEC threshold and dynamically adjusts parameters such as optical power or wavelength to maintain reliable operation during start-up and transient conditions
2Reliability
If forward error correction is applied, then error correction is provided, but it cannot correct errors when BER exceeds the threshold
Solution Approach 1:
The system applies dynamics by making optical parameters adjustable rather than fixed. During start-up or degraded conditions, the system dynamically modifies parameters such as optical launch power, wavelength, or component settings based on real-time BER measurements from frame alignment signals, allowing the FEC system to adapt to varying channel conditions and maintain operation within the correction threshold
Solution Approach 2:
The system changes physical parameters of the optical transmission medium to improve signal quality. By adjusting parameters such as optical power levels, wavelength, or component characteristics based on measured bit error rates, the system modifies the transmission channel to reduce errors to within the FEC correction capability, thereby extending the effective error correction range
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces bit error rates to a level where FEC can correct errors, ensuring reliable data transmission even during system start-up by using a feedback loop to adjust parameters and improve signal processing in optical communication systems.
Implementation Method 1
A photodiode is also provided that is configured to convert an optical signal received from the optical component to an electrical signal
Data Source
AI summary
Consistent with the present disclosure, circuitry may be provided in an optical receiver that can determine a bit error rate (BER) associated with an incoming signal by dividing the number of errored bits in a frame alignment signals (FAS) by the number of bits in the FAS. Accordingly, although an optical signal may be severely degraded and forward error correction (FEC) cannot be performed, a BER may be obtained if the FAS can be identified. The BER can then be used in a feedback loop to control various optical or electrical components in the receiver to improve or reduce the BER to a level, for example, at which FEC can be performed.