PON Bandwidth Allocation Using Virtual Timeslots for Low Latency
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Solution Overview
Problem
Passive optical networks (PONs) face challenges in balancing bandwidth efficiency with low latency demands, particularly for real-time applications like online gaming and video conferencing, due to fixed-size time frames and guard times that create inefficiencies and delays.
Innovation Solution
Implement a dynamic bandwidth allocation (DBA) mechanism with Alloc_ID for latency-sensitive applications, allowing for virtual timeslots and adaptive bandwidth allocation based on service type detection, using a low latency controller to prioritize data transmission and adjust bandwidth dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed-size time frames are used for bandwidth allocation, then bandwidth distribution is simplified, but latency for real-time applications increases
Solution Approach 1:
The patent segments the upstream bandwidth allocation into multiple virtual timeslots within a DBA frame, allowing different services to be allocated different numbers of slots based on their latency requirements. This segmentation enables real-time applications to receive prioritized service while maintaining overall bandwidth distribution simplicity.
Solution Approach 2:
The patent introduces dynamic bandwidth allocation where the OLT can adaptively adjust the number of virtual timeslots allocated to different ONTs based on real-time traffic patterns and service requirements. This dynamic adjustment allows the system to optimize between simplicity and latency performance as needed.
2Reliability
If guard time is inserted between allocations, then data collisions are prevented, but channel goodput decreases
Solution Approach 1:
The patent applies different guard time requirements to different virtual timeslots based on their specific allocation characteristics and service types. Rather than a uniform guard time approach, the system adjusts guard time locally for each allocation to minimize overhead while preventing collisions, thereby optimizing goodput for each service type.
3Productivity
If larger time slots are allocated to minimize overhead, then bandwidth utilization improves, but packet latency increases
Solution Approach 1:
The patent segments the total bandwidth allocation into multiple virtual timeslots, allowing latency-sensitive applications to receive smaller, more frequent allocations with lower latency requirements, while other applications can utilize larger slots for bulk data transfers. This segmentation resolves the contradiction by matching allocation size to service requirements.
Solution Approach 2:
The system dynamically adjusts the size and timing of virtual timeslots based on real-time traffic conditions and service priorities. When latency is critical, the system creates more frequent smaller slots; when bandwidth efficiency is prioritized, larger slots are used, optimizing the balance between utilization and latency for each scenario.
4Reliability
If CBR allocation is used, then constant bandwidth is provided for service reliability, but adaptability to variable application demands is reduced
Solution Approach 1:
The patent extends CBR allocation by making it dynamic rather than static. The OLT can adjust the number of virtual timeslots allocated to each ONT in real-time based on detected traffic patterns and service requirements. This dynamic CBR maintains service reliability through guaranteed minimum allocations while adapting to variable demands through flexible slot adjustment.
Solution Approach 2:
The system incorporates feedback mechanisms where the OLT monitors traffic patterns and service performance, then adjusts CBR allocations accordingly. This feedback loop allows the system to maintain reliability through guaranteed bandwidth while adapting to changing application demands through data-driven allocation optimization.
Data Source
AI summary
The disclosure describes systems and methods for bandwidth allocation in a passive optical network. An optical line terminal (OLT) can communicate with one or more optical network terminals (ONTs). A dynamic bandwidth allocation (DBA) engine, configured within the OLT, can allocate constant bit rate (CBR) bandwidth for one or more transmission containers from the upstream bandwidth capacity of the PON upon registration of the transmission containers. Each transmission container can be used by an associated ONT for one or more CBR applications. The OLT can receive an indication of the status of a CBR application. The DBA engine, in response to receiving the indication, can adjust the CBR bandwidth usage for the corresponding ONTs in a bandwidth map. The OLT can communicate the updated bandwidth map to the ONTs.