Dynamic Bandwidth Allocation in Passive Optical Networks
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Solution Overview
Problem
Conventional bandwidth allocation methods in passive optical networks (PONs) face challenges in quickly converging the allocated bandwidth to a target bandwidth, as the upper limit of transmission requirements is not suitably controlled, leading to inefficient bandwidth utilization and slow convergence.
Innovation Solution
A dynamic bandwidth allocation method where the optical line terminal (OLT) calculates a requirement threshold based on the time average allocated bandwidth and notifies optical subscriber units, allowing them to transmit data within a specified range, with adjustments using PID computation to optimize threshold control and ensure efficient bandwidth allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the upper limit of transmission requirement is fixed to control bandwidth allocation, then bandwidth utilization efficiency is improved, but the convergence speed of allocated bandwidth to target bandwidth becomes slow
Solution Approach 1:
The patent applies dynamics by making the upper limit of transmission requirement adjustable rather than fixed. The OLT dynamically adjusts this limit based on the difference between time average allocated bandwidth and target bandwidth, allowing the system to adapt between efficiency optimization and convergence speed optimization depending on the operational state.
Solution Approach 2:
The patent changes the parameter of transmission requirement upper limit from a static value to a dynamic value that varies based on bandwidth allocation state. By modifying this parameter according to the convergence needs, the system achieves both efficient bandwidth utilization and fast convergence to target bandwidth.
2Speed
If the transmission requirement upper limit is increased to speed up bandwidth convergence, then convergence speed improves, but bandwidth utilization efficiency deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring the time average allocated bandwidth and comparing it with the target bandwidth. Based on this feedback, the OLT adjusts the transmission requirement upper limit dynamically, creating a closed-loop control system that balances convergence speed and bandwidth utilization efficiency.
Solution Approach 2:
The system transitions from a static transmission requirement limit to a dynamic one that responds to real-time bandwidth allocation conditions. This dynamic adjustment allows the system to optimize both convergence speed and efficiency based on current operational needs.
3Adaptability or versatility
If dynamic bandwidth allocation is implemented without proper threshold control, then bandwidth flexibility is improved, but mismatch between transmission requirement and permission increases
Solution Approach 1:
The patent introduces a dynamically adjusted threshold parameter for transmission requirement that changes based on bandwidth allocation state. This parameter control mechanism maintains bandwidth allocation flexibility while ensuring accurate matching between transmission requirements and permissions by adjusting the threshold according to system conditions.
Solution Approach 2:
The system uses feedback from bandwidth allocation monitoring to adjust the transmission requirement threshold, ensuring that the threshold remains appropriate for current conditions. This feedback mechanism prevents excessive mismatches while preserving the flexibility benefits of dynamic allocation.
Data Source
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AI summary
An object of the present invention is to quickly perform convergence of a time average allocated bandwidth on a target bandwidth. In the invention, an optical line terminal calculates a requirement threshold for each optical subscriber unit based on a difference between the time average allocated bandwidth of each optical subscriber unit and the target bandwidth, and notifies a corresponding optical subscriber unit of the calculated requirement threshold. The corresponding optical subscriber unit then notifies, based on the data amount accumulated in a buffer, the optical line terminal of a data amount, as a transmission requirement, up to a data separation that is less or equal to the notified requirement threshold and in which a maximum transmission amount can be transmitted. The optical line terminal then notifies the corresponding optical subscriber unit of a transmission permission amount in which the data equal to the transmission requirement of which the optical line terminal is notified can be transmitted. The corresponding optical subscriber unit then transmits the data amount corresponding to the transmission permission amount.