IAB Node Cell Power Adaptation for Backhaul Link Constraints
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Solution Overview
Problem
Existing IAB networks face issues with radio link failures (RLF) and service interruptions due to deteriorating backhaul link quality, leading to inefficient resource allocation and increased interference, particularly in integrated access and backhaul scenarios.
Innovation Solution
The proposed solution involves IAB nodes adjusting their downlink transmission power based on backhaul link quality to trigger handovers and reduce the capacity of cell edges, and for high-data-rate UEs, adjusting UL bitrates to align with available backhaul capacity, using MAC CE and DCI-based signaling to minimize RLFs and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IAB nodes maintain high downlink transmission power to serve UEs, then access link capacity is improved, but backhaul link quality deteriorates due to increased interference and capacity constraints
Solution Approach 1:
The patent implements dynamic adaptation of cell coverage parameters (SS/PBCH block power, CSI-RS power, reference signal power) based on real-time backhaul link quality measurements. The IAB node continuously monitors backhaul quality and adjusts access link transmission power accordingly, transforming the static power configuration into a dynamic system that responds to changing backhaul conditions, thereby resolving the contradiction between maintaining high access capacity and preserving backhaul quality
Solution Approach 2:
The patent changes physical transmission parameters (power levels of synchronization signals, broadcast channels, and reference signals) based on backhaul link quality. By adjusting these parameters dynamically, the system adapts the cell coverage and capacity to match the available backhaul capacity, preventing the access link from exceeding what the backhaul can support and thus avoiding RLF events
2Quantity of substance
If IAB nodes increase cell coverage to serve more UEs, then network capacity is improved, but RLF events increase due to mismatched backhaul capacity
Solution Approach 1:
The patent implements a feedback mechanism where the IAB node measures backhaul link quality and uses this information to adjust cell coverage parameters. This closed-loop control ensures that the cell coverage and number of served UEs are continuously adapted to the actual backhaul capacity, preventing overload conditions that would cause RLF events while maximizing the number of UEs that can be served reliably
Solution Approach 2:
The patent performs preliminary adjustment of cell coverage parameters before RLF events occur by proactively monitoring backhaul link quality and adapting access link capacity in advance. This preventive approach allows the system to maintain stability by ensuring that the number of served UEs never exceeds what the backhaul capacity can support, avoiding the need for reactive recovery actions
3Productivity
If IAB nodes allocate more radio resources for access links, then UE service quality is improved, but backhaul link capacity becomes insufficient leading to resource waste
Solution Approach 1:
The patent dynamically changes radio resource allocation parameters based on backhaul link quality measurements. By adjusting the power and capacity of access links to match available backhaul capacity, the system ensures that radio resources are allocated efficiently - neither over-provisioning (which would waste resources) nor under-provisioning (which would degrade service quality). This creates an optimal match between access link resource allocation and backhaul capacity
Data Source
AI summary
Methods and apparatus are provided for adapting a serving cell capacity of an integrated access and backhaul, IAB, node serving one or more wireless devices. In one embodiment a method is performed by the IAB node. The method includes determining a value corresponding to a backhaul link capacity, adapting, based on the determined value, a power level of the serving cell and signalling, to one or more served wireless devices, information indicative of the adapted serving cell power level.