Dynamic Wavelength Bandwidth Allocation for PON Systems
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Solution Overview
Problem
In WDM/TDM-PON systems, existing dynamic bandwidth allocation methods struggle to efficiently distribute total bandwidth to each ONU while minimizing delay quality differences between subscribers, as they are limited to single wavelength time division multiplexing and cannot dynamically change transmission wavelengths.
Innovation Solution
A dynamic wavelength and bandwidth allocation method that allocates wavelengths to ONUs based on target bandwidths calculated from subscription service classes and history information, ensuring the sum of allocated bandwidths across wavelengths does not exceed allocated bandwidth, and adjusts bandwidth allocation to converge to target bandwidths, thereby equalizing wavelength use efficiency and reducing delay differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time slots of variable length are spread in random order in a variable period, then bandwidth allocation flexibility is improved, but delay quality difference between subscribers increases
Solution Approach 1:
The patent applies dynamics by making the allocation period variable rather than fixed. The OLT dynamically adjusts the allocation period length based on traffic conditions and subscriber requirements, allowing the system to adapt between shorter periods for low traffic (reducing delay) and longer periods for high traffic (improving bandwidth utilization). This resolves the contradiction by making the time parameter dynamic rather than static.
Solution Approach 2:
The patent changes the parameter of allocation period from a fixed value to a variable value that can be adjusted based on system conditions. By modifying the time parameter dynamically, the system achieves both flexibility in bandwidth allocation and control over delay quality, resolving the technical contradiction between adaptability and time loss.
2Adaptability or versatility
If wavelength tunability is added to transceiver in OLT, then system capacity and adaptability are improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the transceiver universal by adding wavelength tunability, allowing a single transceiver to operate on multiple wavelengths rather than being dedicated to one wavelength. This multi-functionality enables the same hardware to serve multiple purposes and accommodate varying system capacity requirements, resolving the contradiction between adaptability and complexity through efficient resource utilization.
Solution Approach 2:
The patent introduces dynamic wavelength tuning capability that allows the transceiver to adapt its operating wavelength based on system conditions and traffic requirements. This dynamic behavior enables the transceiver to optimize performance for different scenarios, achieving higher system capacity while managing complexity through intelligent control rather than hardware proliferation.
3Productivity
If bit rate of transceiver is increased from 10G class to 40/100G class, then system capacity is improved, but cost increases
Solution Approach 1:
The patent segments the capacity enhancement into two independent dimensions: wavelength multiplication and time division multiplexing. Instead of requiring a single 40G/100G transceiver, the system uses multiple 10G transceivers operating on different wavelengths with dynamic time slot allocation. This segmentation allows capacity scaling without requiring expensive high-bit-rate transceivers, resolving the contradiction between productivity and manufacturing cost.
Solution Approach 2:
The patent combines multiple 10G transceiver channels into a unified high-capacity system through wavelength division multiplexing and dynamic bandwidth allocation. By merging several lower-cost 10G transceivers that operate simultaneously on different wavelengths, the system achieves 40G/100G equivalent capacity at lower cost, resolving the technical contradiction between system capacity and upgrade cost.
Data Source
AI summary
A wavelength and bandwidth allocation method which includes in order: a wavelength allocation step of allocating each wavelength of an uplink signal to each ONU so that the sum of target bandwidths each allocated as a target to each of the ONUs to which each wavelength of the uplink signal is allocated does not exceed a bandwidth allocated to each wavelength of the uplink signal; and a bandwidth allocation step of allocating a bandwidth to each of the ONUs based on any one of a plurality of requested bandwidths accepted from each of the ONUs in each wavelength of the uplink signal so that the bandwidth actually allocated to each of the ONUs converges to the target bandwidth allocated as a target to each of the ONUs.