Fronthaul Congestion Feedback for Adaptive Radio Resource Allocation
Solution Overview
Problem
Fronthaul networks experience underutilization and congestion, leading to packet loss and increased transport costs, with existing radio resource management systems unable to differentiate between air interface and fronthaul congestion, resulting in inefficient resource allocation and user throughput reduction.
Innovation Solution
Implementing a feedback mechanism for detecting fronthaul congestion through message counters and comparisons, allowing schedulers to adjust link adaptation and radio resource allocations based on accurate congestion information, distinguishing between air interface and fronthaul issues to optimize resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fronthaul is dimensioned to never lose a packet, then packet loss is eliminated, but statistical multiplexing gain is limited and transport costs increase
Solution Approach 1:
The patent implements a feedback mechanism where the radio unit monitors fronthaul congestion status and sends congestion indication messages to the distributed unit. This feedback allows the system to dynamically adjust resource allocation based on actual congestion conditions, eliminating the need for over-provisioning while maintaining acceptable packet loss rates. The congestion indication triggers adaptive responses that optimize the balance between reliability and cost.
Solution Approach 2:
The system transitions from a static, over-provisioned fronthaul dimensioning to a dynamic approach where resource allocation adapts to real-time congestion conditions. The congestion indication mechanism enables the system to flexibly adjust traffic handling, statistical multiplexing ratios, and resource allocation based on actual load conditions, maximizing statistical multiplexing gains while maintaining service quality.
2Reliability
If fronthaul congestion occurs and HARQ retransmissions are triggered, then packet loss is recovered, but air interface resources are consumed and congestion is exacerbated
Solution Approach 1:
The patent applies preliminary anti-action by proactively detecting fronthaul congestion before packet loss occurs and triggering preventive measures. When congestion is detected, the system adjusts resource allocation, modifies statistical multiplexing parameters, or implements traffic shaping to prevent packet loss at its source, thereby avoiding the need for HARQ retransmissions and their associated air interface resource consumption.
3Measurement precision
If radio resource management assumes loss is due to air interface, then air interface resources are adjusted, but fronthaul congestion is not addressed and resource allocation becomes inefficient
Solution Approach 1:
The patent implements feedback by having the radio unit monitor fronthaul congestion status and communicate this information to the distributed unit's scheduler. This feedback mechanism enables the scheduler to accurately identify whether packet loss or congestion is caused by fronthaul issues or air interface conditions, allowing for precise and efficient resource allocation decisions that address the root cause rather than applying generic corrections.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Disclosed are devices, methods, apparatuses, and computer readable media for fronthaul. An example apparatus for a scheduler may include at least one processor and at least one memory. The at least one memory may store instructions that, when executed by the at least one processor, may cause the apparatus at least to: monitor a feedback notifying a status of congestion in fronthaul; and perform at least one of the following: adjusting link adaptation, or adjusting radio resource allocations with a radio resource limit which restricts an amount of radio resources available per a time interval for a given cell or a group of cells.