Hierarchical Modulation Enhancement Layer Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical communication systems face challenges in improving bit-error rates due to noise and signal distortions in hierarchical modulation, particularly in the enhancement layers, which are more vulnerable to noise and distortions during transmission.
Innovation Solution
The implementation of hierarchical modulation in optical transport systems, where additional data streams are encoded onto enhancement layers of multiple hierarchically modulated optical waves, allowing for redundant transmission and noise reduction through signal averaging in the receiver, using optical de-multiplexers, base-layer decoders, enhancement-layer superposition, and decoders to recover the additional data stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hierarchical modulation is used to increase data transmission capacity, then productivity is improved, but reliability deteriorates due to noise vulnerability in enhancement layers
Solution Approach 1:
The patent transmits multiple copies of the enhancement layer data stream across different optical channels. Each channel carries a redundant copy of the enhancement layer, allowing the receiver to combine these copies to improve signal quality and reduce bit-error rates while maintaining high data transmission capacity
Solution Approach 2:
The receiver merges the enhancement layer signals from multiple optical channels through coherent combination. By combining the copied enhancement layer signals, the system achieves noise reduction through averaging while preserving the high data capacity enabled by hierarchical modulation
2Productivity
If enhancement layers are used to carry additional data streams, then productivity is improved, but object-affected harmful factors worsen due to increased noise and signal distortions
Solution Approach 1:
Multiple copies of the enhancement layer are transmitted across separate optical channels, allowing the receiver to select or combine the cleanest signals and discard or average out noisy components, thereby reducing the impact of noise and distortions while maintaining high data capacity
Solution Approach 2:
The patent uses multiple optical channels as intermediaries to transmit the enhancement layer data. By distributing the enhancement layer across multiple channels and then combining them at the receiver, the system mediates the harmful effects of noise and distortions through diversification and averaging
Data Source
AI summary
We disclose an optical transport system configured to transport an additional data stream using hierarchical modulation. In an example embodiment, copies of the additional data stream are encoded onto enhancement layers of multiple hierarchically modulated optical waves transported through the system in a multiplexed manner. An optical receiver coupled to a remote end of the optical transport link is configured to use this redundant transmission of the additional data stream to improve the bit-error rate thereof, e.g., by first extracting the signal components corresponding to the enhancement layers of the different hierarchically modulated optical waves and then combining the extracted signal components in a manner that tends to reduce, through averaging, the relative magnitude of noise in the combined signal compared to that in the individual extracted signal components. The disclosed signal-transmission format is suitable for various types of multiplexing, e.g., any combination of space-, wavelength-, and polarization-division multiplexing.