Optical Path Selection with Flexible Baud Rate and Modulation
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Solution Overview
Problem
Existing optical network technologies fail to effectively combine the flexibility of optical interfaces with control plane knowledge to optimize optical transmission, leading to suboptimal path selection and increased blocking probability.
Innovation Solution
A network controller that determines multiple paths between optical nodes, selects a desired line rate, and accesses path and line rate databases to find feasible paths that match desired optical bandwidth and signal-to-noise ratio requirements, programming optical nodes with optimal [bits/symbol, symbol rate] tuples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical interfaces employ high flexibility in modulation format and symbol rate, then transmission adaptability is improved, but path selection complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting modulation format and symbol rate based on available optical bandwidth and SNR conditions. The system searches through different tuples of [bits/symbol, symbol rate] to find feasible transmission parameters that match the physical layer conditions of each path, thereby achieving high transmission adaptability without manual configuration.
Solution Approach 2:
The control plane utilizes feedback from physical layer metrics (optical bandwidth, SNR) to guide path selection and parameter optimization. The system continuously monitors transmission conditions and uses this feedback to select appropriate paths and configure optical interfaces with suitable modulation formats and symbol rates, resolving the complexity through intelligent control.
2Reliability
If conventional path selection methods are used without combining interface flexibility and control plane knowledge, then system complexity is reduced, but blocking probability increases
Solution Approach 1:
The control plane performs preliminary actions by pre-calculating and storing physical layer metrics (optical bandwidth, SNR) for multiple paths between node pairs. When a transmission request arrives, the system quickly queries these pre-computed metrics and matches them with interface capabilities to determine feasible paths, thereby reducing blocking probability without real-time complex calculations.
Solution Approach 2:
The patent implements a universal path selection mechanism that works across different modulation formats and symbol rates. The control plane maintains a unified view of network paths and their physical layer characteristics, enabling it to handle various transmission requirements (different line rates, formats) through a single multi-functional framework, thus improving reliability without proportionally increasing complexity.
3Productivity
If multiple paths are evaluated with detailed physical layer metrics, then transmission optimization is improved, but computational overhead increases
Solution Approach 1:
The system performs preliminary computation by pre-evaluating and storing physical layer metrics (optical bandwidth, SNR) for all possible paths between node pairs before transmission requests arrive. This offline preparation allows rapid online decision-making when paths need to be selected, reducing computational overhead during actual path selection while maintaining thorough evaluation of transmission conditions.
Solution Approach 2:
The patent applies local quality by focusing detailed physical layer metric evaluation only on paths that are relevant to current transmission requests. The control plane identifies candidate paths based on basic routing criteria first, then applies detailed physical layer analysis only to these candidates, avoiding unnecessary computational overhead on paths that would not be selected anyway.
Data Source
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AI summary
A network controller controls optical nodes configured to communicate with each other at multiple line rates using different tuples of [bits/symbol, symbol rate] for each line rate. The network controller determines multiple paths between two optical nodes, selects a desired line rate at which to communicate between the two optical nodes, and accesses a path database that indicates an available optical bandwidth and an available optical signal-to-noise ratio (SNR) along each path. The network controller determines feasible paths among the paths. To do this, the network controller, for each path, searches the different tuples of the desired line rate for a tuple for which a desired optical bandwidth and a desired optical SNR are accommodated by the available optical bandwidth and the available optical SNR of the path, respectively. The network controller programs optical nodes of one of the feasible paths with a tuple found in the searching.