Channel Monitoring Training Sequence for PAM4 Bit Error Compensation
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Solution Overview
Problem
High bit error rates in PAM4 transmission systems due to reduced signal-to-noise ratio and increased burst errors, requiring lengthy and inefficient long-term bit error testing to ensure reliability, which hampers development efficiency and power adjustment precision in optical modules.
Innovation Solution
Incorporating a channel monitoring training sequence into the data stream, detectable by a sequence identifier, to estimate channel bit error characteristics, allowing for accurate prediction of burst error rates and reducing the need for long-term testing, thereby shortening bit error analysis time and enabling precise power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional long-term bit error testing is performed to ensure system reliability, then the bit error rate requirement is met, but the testing time increases significantly
Solution Approach 1:
The patent applies preliminary action by inserting a channel monitoring training sequence into the data stream before transmission. This training sequence allows the receiving end to estimate channel bit error characteristics in advance, enabling prediction of burst error rates without performing lengthy long-term bit error testing. The training sequence is processed through the same forward error correction and modulation/demodulation as actual data, providing advance information about channel conditions.
Solution Approach 2:
The patent uses copying by creating a channel monitoring training sequence that replicates the structure and processing path of actual data streams. This training sequence copy allows estimation of channel characteristics without requiring actual long-term transmission testing. The sequence identifier enables detection and extraction of this copied training sequence for analysis purposes.
2Quantity of substance
If PAM4 modulation is used to double transmission capacity, then the transmission capacity increases, but the signal-to-noise ratio decreases
Solution Approach 1:
The patent applies feedback by using the channel monitoring training sequence to continuously estimate channel bit error characteristics and burst error rates. This feedback mechanism provides real-time information about channel quality, allowing the system to adapt to the reduced signal-to-noise ratio inherent in PAM4 modulation. The feedback enables prediction of actual transmission performance based on the training sequence results.
Solution Approach 2:
The patent performs preliminary estimation of channel characteristics using the training sequence before actual data transmission. This preliminary action allows the system to anticipate and compensate for the noise effects that will affect PAM4 signals, enabling better error correction and maintaining reliability despite the lower signal-to-noise ratio.
3Reliability
If forward error correction is applied to reduce bit error rate, then the bit error rate decreases, but the complexity of the system increases
Solution Approach 1:
The patent extracts the channel monitoring function from the main data transmission process by using a separate training sequence with a detectable sequence identifier. This extracted monitoring function can estimate channel characteristics without adding significant complexity to the core forward error correction mechanism. The training sequence is processed independently and used to predict error rates, separating the monitoring function from the primary data processing path.
4Object-affected harmful factors
If optical module power is increased to improve signal quality, then the signal-to-noise ratio improves, but the power consumption increases
Solution Approach 1:
The patent replaces the mechanical approach of increasing optical power to improve signal quality with an information-based approach. Instead of brute-forcing better signal quality through higher power, the system uses channel monitoring training sequences to estimate and predict error characteristics. This substitution allows the system to achieve reliable operation through intelligent monitoring and prediction rather than simply increasing power consumption.
Data Source
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AI summary
The present invention discloses a method for compensating a bit error after forward error correction, a coding processing apparatus, and a decoding processing apparatus, to reduce bit error analysis time required after forward error correction, and implement precise adjustment of power of an optical module. The method for compensating a bit error after forward error correction includes: performing, by a coding processing apparatus, forward error correction coding on a first data stream, so as to obtain a second data stream, where the first data stream is received from a Serdes; inserting, by the coding processing apparatus, a preset channel monitoring training sequence into the second data stream, so as to obtain a third data stream, where the channel monitoring training sequence carries a preset sequence identifier; performing, by the coding processing apparatus, modulation and coding processing on the third data stream, so as to obtain a fourth data stream; performing, by the coding processing apparatus, electrical-to-optical conversion processing on the fourth data stream, so as to obtain a fifth data stream; and sending, by the coding processing apparatus, the fifth data stream to a decoding processing apparatus by using an optical signal transmission medium.