ONU–OLT Upstream Allocation for Dynamic Mobile Fronthaul
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Solution Overview
Problem
In centralized radio access networks, the dynamic nature of mobile front-haul traffic leads to significant buffering and latency due to fixed upstream bandwidth allocation cycles that do not adapt quickly enough to varying traffic demands.
Innovation Solution
An optical network unit (ONU) and optical line terminal (OLT) system that dynamically adjusts upstream bandwidth allocation based on real-time monitoring of packet length and rate changes, allowing for frequent recalculations of bandwidth maps to match varying traffic profiles, thereby minimizing latency and ensuring efficient packet transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed upstream bandwidth allocation cycles are used, then device complexity is reduced and system stability is improved, but latency increases and adaptability to varying traffic demands deteriorates
Solution Approach 1:
The patent implements dynamic bandwidth allocation by allowing the ONU to trigger recalculation of the upstream allocation map when traffic profile changes are detected. This transforms the static, fixed-cycle bandwidth allocation into a dynamic system that adapts to real-time traffic conditions, reducing latency during traffic bursts while maintaining system stability through controlled recalculation timing.
Solution Approach 2:
The system changes the allocation cycle parameter from a fixed value to a variable that adjusts based on traffic conditions. When the ONU detects significant traffic profile changes, it triggers a recalculation event, effectively changing the allocation cycle parameter dynamically. This allows the system to maintain long allocation cycles for stability while enabling short cycles when traffic demands change, resolving the contradiction between fixed complexity and adaptive performance.
2Stability of the object's composition
If fixed upstream bandwidth allocation cycles are used, then system stability is improved, but adaptability to varying traffic demands deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the ONU continuously monitors incoming traffic profiles and compares them against threshold changes. When significant changes are detected, the ONU sends a trigger message to the OLT, which then recalculates the upstream allocation map. This feedback loop enables the stable system to adapt to varying traffic demands by initiating recalculation only when necessary, maintaining stability while improving adaptability.
Solution Approach 2:
The system performs preliminary monitoring of traffic profiles at the ONU before triggering recalculation. By continuously observing traffic patterns and detecting changes in advance, the system can proactively initiate bandwidth reallocation before performance degradation occurs. This preliminary action allows the stable fixed-cycle system to adapt to changing traffic demands through advance detection and triggered recalculation.
3Loss of time
If frequent recalculation of bandwidth maps is performed, then adaptability to traffic demands is improved and latency is reduced, but device complexity and processing overhead increase
Solution Approach 1:
Instead of continuously recalculating bandwidth maps, the system performs partial recalculation only when traffic profile changes exceed a predefined threshold. The ONU monitors traffic continuously but triggers recalculation only when necessary, applying partial action rather than excessive continuous recalculation. This reduces processing overhead and device complexity while still achieving low latency by recalculating frequently enough to respond to traffic changes.
Solution Approach 2:
The system implements periodic monitoring of traffic profiles at the ONU, with recalculation triggered at specific intervals when changes are detected. Rather than continuous recalculation, the system uses periodic checks combined with event-triggered recalculation, reducing processing complexity while maintaining low latency through timely updates when traffic patterns change.
Data Source
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AI summary
Example embodiments describe an optical network unit, ONU, and an optical line terminal, OLT, configured to communicate in an optical network and providing communication between a radio unit, RU, and a central unit, CU; the at least one RU sends, via the optical network, packets to the CU respectively comprising a set of frequency domain subcarrier data derived from a time domain symbol for further processing in the CU, wherein the ONU is configured to forward the packets from the at least one RU in accordance with a upstream allocation map to the OLT and to perform: monitoring a length of the packets and a rate of the packets; detecting a change in the length and/or the rate of the packets; and notifying the OLT of the change for adapting the upstream allocation map for the ONU.