WSS Channel Interleaving for Uniform BER in Optical Super-Channels
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Solution Overview
Problem
Wavelength selective switch (WSS) filter-based impairments in WDM optical communication systems lead to bit error rate disparities across channels, degrading network performance due to non-ideal pass-band filtering, which results in unacceptable information loss and reduced signal quality.
Innovation Solution
Implementing techniques such as comparative channel pre-emphasis, differentiated channel modulation formats, multi-channel forward error correction interleaving, differentiated channel baud rates, and selective subcarrier adjustments to mitigate the impact of WSS filter-based impairments, ensuring more uniform bit error rates across channels and enhancing network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If WSS filter-based routing is used to route optical signals, then channel selectivity and routing flexibility are improved, but bit error rate disparities and signal quality degradation occur due to non-ideal pass-band filtering
Solution Approach 1:
The patent applies local quality by implementing channel-specific pre-emphasis equalization where each optical channel receives customized equalization parameters tailored to its specific impairment profile. The system determines individual pre-emphasis values for each channel based on its attenuation characteristics through the WSS filter, allowing targeted compensation rather than uniform treatment across all channels.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting pre-emphasis equalization parameters for different channels to compensate for WSS filter-induced impairments. The system varies the equalization parameters based on measured or estimated channel-specific attenuation characteristics, transforming the uniform signal into channel-adapted signals that compensate for differential filtering effects.
2Productivity
If multiple optical signals are combined into super-channels for higher data rate transmission, then transmission capacity is improved, but bit error rate disparities across constituent channels increase due to differential filter attenuation
Solution Approach 1:
The patent applies segmentation by treating each optical channel within a super-channel as a separate entity requiring individual equalization. Instead of applying a single equalization scheme to the aggregated super-channel, the system segments the equalization process into channel-specific operations, determining and applying unique pre-emphasis parameters to each constituent channel to address its specific impairment profile.
Solution Approach 2:
The patent implements local quality by providing differentiated pre-emphasis equalization to each channel within the super-channel based on its specific attenuation characteristics. Edge channels experiencing greater filter attenuation receive different equalization treatment compared to center channels, ensuring uniform bit error rate performance across all channels despite their different positions in the spectral filter response.
3Reliability
If pre-emphasis equalization is applied to compensate for WSS filter attenuation, then signal quality at the receiver is improved, but transmission power requirements increase
Solution Approach 1:
The patent applies partial or excessive action by implementing pre-emphasis equalization only to the extent necessary to compensate for measured or estimated WSS filter attenuation. Rather than applying maximum equalization across all channels, the system applies channel-specific pre-emphasis values that are calibrated to provide just sufficient compensation for each channel's impairment profile, optimizing the trade-off between signal quality improvement and transmission power consumption.
Data Source
AI summary
A method may include interleaving, by an optical device, a set of bits of a first channel with a set of bits of a second channel. The first channel may include first forward error correction (FEC) data associated with the set of bits of the first channel and the second channel may include second FEC data associated with the set of bits of the second channel. The method may further include transmitting first information via the first channel and second information via the second channel. The first information may include a portion of the set of bits of the first channel, a portion of the set of bits of the second channel, and the first FEC data. The second information may include another portion of the set of bits of the first channel, another portion of the set of bits of the second channel, and the second FEC data.