Optical Super-Channel Coding for Decodable Inter-Channel Interference
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Solution Overview
Problem
Coherent optical communications face challenges in transmitting data over optical super-channels due to inter-channel interference (ICI), which is currently treated as noise, leading to reduced transmission rates and increased noise levels.
Innovation Solution
The approach involves jointly decoding data from neighboring sub-channels with lower noise, shaping the ICI spectrum to increase decodable power, and using dirty-paper coding to align interference, along with adaptive coding rates and power arrangements to maximize reliability and data rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gap between wavelengths of sub-channels is decreased to operate as a single wideband channel, then the data transmission rate is improved, but inter-channel interference (ICI) increases causing additional noise in received signals
Solution Approach 1:
The patent applies dirty-paper coding to convert the harmful ICI into beneficial information. By treating ICI as decodable data rather than noise, the system uses the interference itself to carry additional information, thereby increasing the proportion of decodable data and improving transmission rates without requiring larger frequency gaps between sub-channels
2Object-affected harmful factors
If conventional filtering is applied to minimize ICI, then the noise in received signals is reduced, but the transmission rate is reduced due to suppression of data in the transmitted signal
Solution Approach 1:
Instead of filtering out ICI as conventional systems do, the patent inverts the approach by treating ICI as decodable data. The system jointly decodes data from multiple sub-channels including the ICI components, thereby converting the filtering problem into a joint decoding opportunity that increases rather than decreases transmission rate
3Reliability
If data streams are partitioned into multiple smaller portions for joint decoding, then the reliability of decoding is improved, but the device complexity increases
Solution Approach 1:
The patent partitions data streams into multiple smaller portions that can be jointly decoded across sub-channels. This segmentation allows the receiver to process ICI as decodable data in manageable chunks, improving reliability through diversity while the computational complexity is distributed across multiple decoding operations rather than requiring a single complex decoder
Data Source
AI summary
The transmission of data from a transmitter to a receiver over an optical super-channel including a set of sub-channels of different frequencies includes partitioning the data into a set of data streams including one data stream for each sub-channel and partitioning each data stream into a set of sub-streams. Each sub-stream of each data stream is encoded with different forward error correction (FEC) codes to produce a set of encoded sub-streams for each data stream, and the set of encoded sub-streams of each data stream are superimposed with different powers to produce a set of encoded data streams. The set of encoded data streams is multiplexed to produce an optical signal transmitted over the set of sub-channels of the optical super-channel.