WDM PON Resource Scheduling for Latency and Capacity
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Solution Overview
Problem
Current optical networks face challenges in efficiently managing time-sensitive fronthaul signals with high bandwidth requirements and deterministic delays, particularly in coexisting with fixed access networks, where different types of communication traffic have varying latency and bandwidth needs.
Innovation Solution
A method and apparatus for scheduling resources in a Wavelength Division Multiplexed (WDM) Passive Optical Network (PON) that dynamically allocates time slots and optical wavelengths based on notification messages from Optical Network Terminals (ONTs), allowing for concurrent handling of mobile radio and fixed access traffic, using a central hub with a scheduler and Slot Assignment Logic (SAL) to prioritize and reconfigure resources in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time division multiplexing is used to share wavelengths among multiple ONTs, then network capacity is improved, but latency for time-sensitive fronthaul traffic increases
Solution Approach 1:
The patent segments the optical network into different wavelength channels, with dedicated wavelengths for time-sensitive fronthaul traffic and shared wavelengths for fixed access traffic. This segmentation allows fronthaul traffic to bypass time division multiplexing delays while TDM continues to serve fixed access customers, resolving the contradiction between network capacity and latency.
Solution Approach 2:
The patent introduces wavelength as an additional dimension for traffic differentiation beyond traditional time division multiplexing. By assigning specific wavelengths to fronthaul traffic and others to fixed access traffic, the system creates a multi-dimensional resource allocation framework that simultaneously optimizes for both capacity and latency requirements.
2Reliability
If dedicated wavelengths are assigned to point-to-point connections, then deterministic delays are achieved, but network resource utilization decreases
Solution Approach 1:
The patent applies local quality by providing deterministic wavelength assignments only where needed (fronthaul connections requiring time-sensitive performance) while using shared TDM wavelengths for fixed access traffic where deterministic delays are less critical. This localized application of dedicated resources optimizes the balance between reliability and resource utilization.
Solution Approach 2:
The system dynamically allocates wavelengths based on traffic type requirements, with the ability to switch between dedicated and shared wavelength modes. This dynamic resource allocation allows the network to provide deterministic delays when necessary while maximizing resource utilization during periods when dedicated assignments are not required.
3Productivity
If multiple traffic types are handled on the same optical network, then infrastructure efficiency is improved, but QoS differentiation becomes difficult to maintain
Solution Approach 1:
The patent uses wavelength as an additional dimension to differentiate QoS for multiple traffic types on the same optical network. By assigning specific wavelengths to fronthaul traffic and others to fixed access traffic, the system maintains clear QoS boundaries while efficiently utilizing the shared optical infrastructure.
Solution Approach 2:
The patent segments traffic handling by wavelength, creating distinct transmission channels for different traffic types with different QoS requirements. This segmentation allows the network to maintain strict QoS differentiation for time-sensitive fronthaul traffic while simultaneously serving fixed access customers on shared wavelengths, thereby preserving infrastructure efficiency.
Data Source
AI summary
A method for scheduling resources for a Wavelength Division Multiplexed, WDM, Passive Optical Network, PON. The WDM PON comprises a central hub (201) and a plurality of remote Optical Network Terminals, ONTs, (220) handling different types of communications traffic. The method (450) comprises receiving (452) a notification message from the plurality of remote Optical Network Terminals, ONTs, indicating a loading status of the ONT, and allocating (454) one or more slots to a plurality of the ONTs based on the received notification messages from the ONTs, wherein the plurality of ONTs (220) handle different types of communications traffic. The slots (301) are allocated based on the received notification messages as a time slot which is time division multiplexed with further time slots, and the slots are further allocated based on the received notification messages as an optical wavelength of a plurality of optical wavelengths of the WDM PON.