Adaptive LDPC Multiband Modulation for Ultra-High-Speed Optical Transport
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Solution Overview
Problem
High-speed optical Ethernet technologies face limitations due to limited bandwidth, high energy consumption, and heterogeneity of optical networking infrastructure, which hinder reliable communication and error correction performance, especially at ultra-high speeds beyond 1 Tb/s.
Innovation Solution
An adaptive software-defined Low Density Parity Check (LDPC) coded multiband modulation system employing hybrid multidimensional coded modulation with orthogonal prolate spheroidal wave functions, utilizing both electrical and optical degrees of freedom, including spatial and polarization modes in few-mode fibers, to enable ultra-high-speed data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polarization-division multiplexed (PDM) single-carrier QAM systems use extremely large signal constellation sizes to reach ultra-high-speed transport rates beyond 1 Tb/s, then data transmission rate is improved, but system complexity increases
Solution Approach 1:
The patent segments the signal transmission into multiple orthogonal spectral bands (e.g., 5 bands with 20 GHz spacing) that can be independently processed and transmitted. Each band carries a portion of the data stream, allowing the overall high data rate to be achieved through parallel transmission rather than requiring a single extremely large constellation, thereby reducing system complexity while maintaining high productivity
Solution Approach 2:
The patent transitions from traditional time-domain single-carrier modulation to frequency-domain multi-band modulation by introducing orthogonal spectral bands as an additional dimension for data transmission. This dimensional change allows data to be transmitted across multiple frequency channels simultaneously, achieving ultra-high speeds without requiring excessively large signal constellations in a single channel
2Productivity
If operating symbol rates are increased to achieve higher data rates, then productivity is improved, but fiber nonlinearities and polarization-mode dispersion deteriorate communication reliability
Solution Approach 1:
By dividing the high-rate data stream into multiple lower-rate parallel bands transmitted on orthogonal frequencies, the patent reduces the symbol rate requirement for each individual channel. This segmentation allows operation at lower symbol rates that are less susceptible to fiber nonlinearities and PMD, thereby maintaining communication reliability while achieving high overall data rates through the combined capacity of multiple bands
Solution Approach 2:
The patent changes the operating parameters by distributing data across multiple spectral bands with specific center frequencies and spacing (e.g., 20 GHz spacing). This parameter change allows the system to operate in a regime where fiber nonlinearities and PMD have reduced impact compared to single high-speed channels, improving reliability while maintaining high productivity
3Productivity
If 100 GbE and higher standards are implemented to meet bandwidth demands, then data transmission capacity is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic orthogonal spectral bands that can be activated or deactivated based on traffic demands. This periodic structure allows the system to allocate energy efficiently across multiple bands, activating only the necessary number of bands for current traffic requirements rather than continuously operating at maximum capacity, thereby reducing energy consumption while maintaining high bandwidth capacity when needed
Data Source
AI summary
Systems and methods for transmitting data, including encoding one or more streams of input data using one or more adaptive Low Density Parity Check (LDPC) encoders, wherein the encoders generate one or more signal constellations; modulate one or more signals using hybrid multidimensional coded modulation; apply orthogonal prolate spheroidal wave functions as electrical basis functions; generate one or more spectral band group signals by selecting and combining two or more spectral band groups with center frequencies that are orthogonal to each other; and spectral-mode-multiplex and transmit the one or more adaptive LDPC-coded data streams including the one or more spectral band group signals combined into corresponding spatial modes over a transmission medium.