PON Bandwidth Allocation Segmentation for Latency Reduction
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Solution Overview
Problem
Current dynamic bandwidth allocation (DBA) schemes in Passive Optical Networks (PONs) face challenges in supporting a large number of users, leading to increased latency and reduced bandwidth efficiency, especially when the number of users exceeds 64, due to significant guard interval overhead and reduced usable bandwidth.
Innovation Solution
A generic and flexible DBA architecture and polling scheme that aggregates and groups users based on latency requirements, reducing the number of guard intervals and increasing usable bandwidth by allocating time slots dynamically, while maintaining compatibility with existing multipoint control protocol (MPCP) standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of users in PON is increased beyond 64, then the network capacity and user coverage are improved, but the latency increases and bandwidth efficiency deteriorates due to significant guard interval overhead
Solution Approach 1:
The patent segments the upstream bandwidth allocation into multiple DBA cycles, where each cycle serves a subset of ONUs. This segmentation reduces the number of guard intervals needed within each cycle, thereby reducing total latency while still supporting a large overall number of users across multiple cycles.
Solution Approach 2:
The patent implements periodic DBA cycles that repeatedly allocate bandwidth to different groups of ONUs. By organizing user service into periodic cycles with optimized duration, the system manages large user populations efficiently while controlling per-cycle latency and guard interval overhead.
2Quantity of substance
If the number of users in PON is increased beyond 64, then the network capacity and user coverage are improved, but the bandwidth efficiency deteriorates due to significant guard interval overhead
Solution Approach 1:
The patent segments the upstream bandwidth allocation into multiple DBA cycles, where each cycle serves a subset of ONUs. This segmentation reduces the number of guard intervals needed within each cycle, thereby reducing total latency while still supporting a large overall number of users across multiple cycles.
Solution Approach 2:
The patent changes the parameter of DBA cycle configuration to optimize bandwidth efficiency. By adjusting cycle duration, number of cycles, and ONUs per cycle, the system minimizes guard interval overhead while maintaining support for large numbers of users, thus improving overall bandwidth efficiency.
3Loss of information
If a traditional DBA scheme polls all users to gather bandwidth requests, then complete bandwidth information is obtained, but the latency overhead increases significantly when the number of users exceeds 64
Solution Approach 1:
The patent segments the polling process into multiple DBA cycles, where each cycle polls a subset of ONUs. This segmentation allows complete bandwidth information to be gathered across all ONUs over multiple cycles, while reducing per-cycle polling latency and guard interval overhead compared to polling all ONUs in a single cycle.
Solution Approach 2:
The patent implements periodic DBA cycles that repeatedly allocate bandwidth to different groups of ONUs. By organizing user service into periodic cycles with optimized duration, the system manages large user populations efficiently while controlling per-cycle latency and guard interval overhead.
Data Source
AI summary
A method for allocating bandwidth to a first ONU, a second ONU, M1 ONUs, and M2 ONUs includes, during an allocation cycle, (i) granting a respective upstream time slot to, of a plurality of N ONUs, only each of the M1 ONUs, and (ii) granting a first upstream time slot to the first ONU. Each of the M1 ONUs and M2 ONUs is one of the plurality of N ONUs. The method also includes, during a subsequent cycle, (i) granting a respective upstream time slot to, of the plurality of N ONUs, only each of the M2 ONUs. The N ONUs includes a skipped-ONU that is one of either, and not both, the M1 ONUs and the M2 ONUs. The method includes, during the subsequent allocation cycle, granting a second upstream time slot to a second ONU, which is not one of the plurality of N ONUs.