Station-Side Apparatus Prioritizing Downlink Frames During Wavelength Switch
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Solution Overview
Problem
In wavelength-tunable WDM/TDM-PON systems, downlink frames addressed to ONUs undergoing wavelength switching experience prolonged delay and communication quality deterioration due to conventional scheduling methods that do not prioritize frames for switch target ONUs during wavelength switch processes.
Innovation Solution
A station-side apparatus is configured with a storage apparatus and transmission unit that manages and prioritizes downlink frames based on whether they are addressed to ONUs whose wavelength is being switched, ensuring swift transmission during wavelength switch processes by determining the transmission order based on management information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional scheduling methods are used to transmit downlink frames during wavelength switch processes, then the transmission control is simple, but the delay time for frames addressed to switch target ONUs becomes prolonged and communication quality deteriorates
Solution Approach 1:
The OLT determines in advance whether each ONU is a switch target before initiating wavelength switching. This preliminary identification allows the system to prepare and prioritize frame transmission for affected ONUs, reducing delay by avoiding last-minute scheduling adjustments and enabling proactive frame evacuation during the wavelength switch process.
Solution Approach 2:
The patent applies different transmission priorities to different types of frames based on their destination. Frames addressed to switch target ONUs are given high priority for expedited transmission, while frames to non-switch target ONUs follow conventional scheduling. This localized differentiation of transmission quality ensures that only the affected frames experience priority treatment, minimizing overall system complexity while addressing the specific delay problem.
2Productivity
If the OLT transmits downlink frames to non-switch target ONUs during wavelength switch processes, then the transmission process is continuous, but frames addressed to switch target ONUs experience prolonged delay
Solution Approach 1:
Before the wavelength switch begins, the OLT identifies which ONUs are switch targets and prepares to prioritize their frame transmission. This advance preparation ensures that when frames need to be transmitted during the switch process, the OLT can immediately direct high-priority transmission to the correct ONUs, maintaining overall transmission efficiency while preventing delay to affected frames.
Solution Approach 2:
The patent implements dynamic frame prioritization based on real-time conditions. During wavelength switch processes, the transmission control dynamically adjusts priorities: frames to switch target ONUs receive high priority treatment, while frames to non-switch target ONUs continue with standard scheduling. This dynamic adaptation allows the system to maintain continuous transmission productivity while addressing the specific timing needs of affected frames.
3Reliability
If the OLT uses conventional priority scheduling for downlink frames, then the control mechanism is simple, but communication quality for switch target ONUs deteriorates due to extended delay
Solution Approach 1:
The OLT performs preliminary identification of switch target ONUs before initiating wavelength switching. This advance determination allows the system to pre-configure frame prioritization rules and evacuation strategies, ensuring reliable communication quality for affected frames without requiring complex real-time decision-making mechanisms during the actual transmission process.
Solution Approach 2:
The patent implements selective quality treatment by applying different priority levels to different frame destinations. Frames addressed to switch target ONUs receive enhanced priority and expedited transmission, while frames to non-switch target ONUs follow conventional scheduling rules. This localized quality differentiation improves communication reliability for affected frames while keeping the overall control mechanism relatively simple by only affecting a subset of frames.
Data Source
AI summary
Provided is a station-side apparatus configured to conduct optical communication with a plurality of subscriber apparatuses via a plurality of wavelengths. The station-side apparatus includes a storage apparatus, management information stored in the storage apparatus and configured to indicate whether or not a subscriber apparatus is a first apparatus whose wavelength used for communication is changed to another wavelength, and a transmission unit configured to transmit downlink frames addressed to the plurality of subscriber apparatuses in an order of transmission determined based on the management information.