Subcarrier Deactivation for Optical Reach in DWDM Networks
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Solution Overview
Problem
Optical impairments such as non-linear effects and noise in DWDM optical networks reduce the optical signal to noise ratio (OSNR), making it challenging to maintain signal strength and feasibility over longer distances, as existing technologies do not adequately consider these impairments in path determination.
Innovation Solution
The method involves transmitting data signals over a subset of optical subcarriers instead of the entire group, with at least one inactive subcarrier between active ones, to reduce non-linear effects and increase optical reach, while deactivating unnecessary subcarriers to improve OSNR and extend signal distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a group of optical subcarriers is used to transmit data signal, then data rate is increased, but non-linear effects and noise increase reducing OSNR and optical reach
Solution Approach 1:
The patent segments the group of optical subcarriers into active and inactive subsets. By transmitting the data signal only over a subset of subcarriers rather than the entire group, the system reduces non-linear effects and noise accumulation, thereby maintaining acceptable OSNR levels while still achieving enhanced data rate compared to single-subcarrier systems.
Solution Approach 2:
The patent dynamically changes the parameter of subcarrier activation status. By selectively activating or deactivating specific subcarriers based on optical feasibility assessments, the system adjusts the effective number of active subcarriers to optimize the balance between data rate and OSNR, preventing degradation below acceptable thresholds.
2Quantity of substance
If all subcarriers in a group are activated for transmission, then bandwidth utilization is maximized, but optical impairments accumulate reducing signal feasibility over distance
Solution Approach 1:
The patent extracts or removes specific subcarriers from the active transmission set when optical feasibility assessments indicate that their inclusion would cause cumulative optical impairments to exceed acceptable thresholds. This selective removal of problematic subcarriers maintains bandwidth utilization through the remaining active subset while preventing signal degradation over long distances.
3Length of stationary object
If subcarriers are deactivated to reduce non-linear effects, then optical reach is improved, but data rate decreases
Solution Approach 1:
The patent implements a dynamic subcarrier activation strategy where the system continuously assesses optical feasibility and adjusts the subset of active subcarriers accordingly. This dynamic approach allows the system to maximize data rate when optical conditions permit while automatically reducing to a smaller active subset when reaching extended distances, thereby optimizing the trade-off between optical reach and data rate based on real-time network conditions.
Data Source
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AI summary
Various example embodiments are disclosed. According to an example embodiment, a method may include determining that a transmission of a data signal over a path of a wavelength division multiplexed (WDM) optical network using a group of optical subcarriers is not optically feasible; determining that the transmission of the data signal over the path using a subset of the group of optical subcarriers is optically feasible; activating subcarriers for the subset of optical carriers while deactivating one or more optical subcarriers of the group, at least one deactivated subcarrier provided between at least two activated subcarriers of the group; and transmitting the data signal over at least a portion of the path using the activated subcarriers of the group.