SER-Based Transmitter Tuning for Non-Linear Optical Systems
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Solution Overview
Problem
Conventional transmitter tuning methods based on signal levels are not optimal as they average out noise and do not effectively account for noise in the equalization process, particularly in non-linear optical transmitters.
Innovation Solution
The method employs a symbol-error-rate (SER) based tuning approach using a sequence selective pseudorandom binary sequence (PRBS) or Short Stress Pattern Random Quaternary (SSPRQ) checker to compare transmitted and expected binary sequences, generating error count and ratio data to tune the transmitter's Look-Up Table (LUT) and improve signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If signal levels are used as a metric for tuning the transmitter, then the tuning process is simplified, but noise is averaged out and not factored in, resulting in suboptimal equalization performance
Solution Approach 1:
The patent changes the tuning metric from signal levels to symbol error rate (SER). Instead of using averaged signal level measurements, the system transmits known training sequences, compares received symbols with expected symbols, and calculates SER as the ratio of erroneous symbols to total symbols. This parameter change enables noise to be factored into the tuning process, improving equalization accuracy while maintaining operational simplicity through automated SER-based feedback control.
2Ease of manufacture
If conventional linear Feed-Forward Equalizer (FFE) is employed for equalization, then the implementation is straightforward, but it cannot effectively compensate for non-linear effects in optical transmitters
Solution Approach 1:
The patent transitions from static linear FFE coefficients to dynamic adaptive coefficients that are continuously optimized based on SER measurements. The system employs training sequences to estimate channel characteristics and adjust equalizer parameters adaptively, enabling effective compensation for non-linear effects while maintaining implementation feasibility through standardized adaptive filtering algorithms.
Solution Approach 2:
The patent introduces SER-based feedback control where the symbol error rate is continuously measured and used to adjust equalizer parameters. The feedback loop transmits training sequences, measures SER, and iteratively optimizes equalization parameters to minimize errors, enabling effective compensation for non-linear transmitter effects while maintaining straightforward implementation through feedback-driven adaptation.
Data Source
AI summary
Embodiments are disclosed for a sequence selective symbol checker for communication systems. An example method includes configuring a symbol checker of a receiver with first binary sequence data generated by a symbol generator of the receiver. The example method also includes comparing, using the symbol checker, second binary sequence data provided by a transmitter to the first binary sequence data to generate error count data related to a number of errors for symbols associated with the second binary sequence data. The example method also includes determining total count data related to a number of symbols associated with the first binary sequence data. The example method also includes determining error ratio data associated with the transmitter based on the error count data and the total count data.