Channel Map for Optical Network Unit Activation
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Solution Overview
Problem
Multi-wavelength passive optical networks (MW-PONs) face challenges in activating optical network units (ONUs) on correct wavelength channels, preventing rogue transmissions, and ensuring backward compatibility with legacy ONUs, while existing technologies are inefficient and suboptimal in bandwidth usage and require frequent quiet windows.
Innovation Solution
The MW-PON system employs a broadcast management message to convey information about bi-directional wavelength channels, allowing ONUs to perform tuning range scanning, channel map acquisition, and parameter learning, enabling them to select and activate on physically reachable and operationally available channels, preventing rogue transmissions by ensuring compatible wavelength usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple wavelengths are used for transmitting data over existing fiber optic networks, then data carrying capacity is improved, but operational complexity and difficulty of detecting and measuring wavelength allocation increases
Solution Approach 1:
The patent introduces a channel map message as an intermediary information structure that mediates between the OLT's wavelength allocation decisions and the ONUs' wavelength selection. This message contains channel map information that guides ONUs to select appropriate wavelengths without requiring complex centralized control or frequent quiet windows, thus resolving the contradiction between increased data capacity and wavelength management complexity
Solution Approach 2:
The patent enables ONUs to autonomously select wavelengths by providing them with channel map information through the broadcast message. Each ONU can independently determine its operating wavelength based on the channel map and its own tuning capabilities, eliminating the need for complex OLT-controlled wavelength assignment procedures and frequent quiet windows
2Adaptability or versatility
If traditional activation methods are used in MW-PON systems, then backward compatibility with legacy ONUs is maintained, but bandwidth efficiency decreases and frequent quiet windows are required
Solution Approach 1:
The patent designs the channel map message to serve multiple functions simultaneously: it provides wavelength allocation information to tunable ONUs for efficient wavelength selection, while also being compatible with legacy ONUs that ignore the message and use traditional activation methods. This universal message structure enables both new and legacy ONUs to coexist on the same network without requiring frequent quiet windows, thus improving bandwidth efficiency while maintaining backward compatibility
3Ease of operation
If ONUs are allowed to transmit on any wavelength within their tuning range, then ease of operation is improved, but rogue transmissions on incorrect wavelength channels increase
Solution Approach 1:
The patent implements a feedback mechanism where the OLT broadcasts channel map information that reflects the current wavelength allocation status. ONUs use this feedback information to select wavelengths that are currently available and appropriate for their service requirements. This feedback loop prevents rogue transmissions by ensuring ONUs only select wavelengths that are currently allocated and appropriate for their tuning capabilities and service needs
Data Source
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AI summary
A multi-wavelength passive optical network (MW-PON) includes an optical distribution network (ODN), a plurality of optical line terminations (OLTs) and an optical network unit (ONU). The ODN includes a trunk fiber, one or more branching elements, and a plurality of distribution fibers. Each OLT is associated with an individual bi-directional wavelength channel using a corresponding single downstream wavelength and a corresponding single upstream wavelength, and supporting a specific downstream line rate and one or more distinct upstream line rates. The ONU is communicatively coupled to a respective distribution fiber, being tunable over a specific range of downstream wavelengths and a specific range of upstream wavelengths, and supporting a specific downstream line rate and a specific upstream line rate. The OLT is configured to assemble a broadcast management message conveying information about bi-directional wavelength channels in said MW-PON system and transmit said message downstream over the associated bi-directional wavelength channel.