IAB-Donor CU Link Congestion Detection in 5G Networks
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Solution Overview
Problem
In integrated access and backhaul (IAB) networks, especially in 5G NR systems, there is a challenge in detecting and managing link congestion or blockage across multi-hop connections, which can hinder proper data traffic path establishment due to the lack of direct feedback from IAB-nodes to the IAB-donor CU, leading to inefficient data transmission.
Innovation Solution
A method where IAB-nodes with multi-hop connections can notify the IAB-donor CU about congestion or blockage on backhaul RLC channels, allowing the CU to stop or reduce transmission and establish an alternative path, involving downlink transmission, information reception, and feedback forwarding through the CU and DU of the IAB-donor gNB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If IAB-nodes with multi-hop connections are used to extend network coverage, then network coverage and flexibility are improved, but the ability to detect and manage link congestion deteriorates due to lack of direct feedback from IAB-nodes to IAB-donor CU
Solution Approach 1:
The patent introduces an intermediary feedback mechanism where IAB-nodes send congestion information to IAB-donor CU through a multi-step process: IAB-node detects congestion -> sends indication to IAB-donor DU -> DU forwards to CU. This intermediary chain resolves the information loss problem in multi-hop connections while maintaining extended network coverage.
2Productivity
If downlink transmission continues without congestion detection, then data transmission efficiency is maintained, but network performance deteriorates due to inability to mitigate link congestion or blockage
Solution Approach 1:
The patent implements a feedback mechanism where IAB-nodes continuously monitor backhaul RLC channel status and send congestion indications to the IAB-donor CU. The CU then adjusts downlink transmission accordingly, stopping or reducing transmission when congestion is detected. This feedback loop maintains reliability while preserving transmission efficiency through dynamic adaptation.
3Reliability
If IAB-donor CU stops or reduces downlink transmission upon receiving congestion information, then network reliability is improved by mitigating congestion, but data transmission productivity deteriorates due to reduced transmission volume
Solution Approach 1:
The patent applies dynamic control where the IAB-donor CU adjusts downlink transmission levels based on real-time congestion feedback. Rather than permanent stopping, the system dynamically modulates transmission volume according to channel conditions, maintaining reliability through adaptive control while minimizing impact on overall transmission productivity.
Data Source
AI summary
A method and apparatus for supporting a link congestion detection in a in an integrated access and backhaul (IAB) network is provided. An IAB-donor-central unit (CU) performs downlink (DL) transmission, receives information about a problem on a backhaul (BH)-radio link control (RLC) channel between a first IAB-node and a second IAB-node, and stop/reduces the DL transmission to the second IAB-node via the BH-RLC channel between the first IAB-node and the second IAB-node based on the information. The IAB-donor-CU may select a path towards the second IAB-node other than the BH-RLC channel between the first IAB-node and the second IAB-node, and perform DL transmission towards the second IAB-node via the selected path.