IAB Node Crosslink Interference Mitigation via Beam Power Control
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Solution Overview
Problem
Integrated Access and Backhaul (IAB) systems face crosslink interference (CLI) issues due to the coexistence of different link directions over the same frequency resources in adjacent cells, leading to user-to-user and base-station-to-base-station interference, which affects the reliability and performance of wireless backhaul links.
Innovation Solution
A node in the IAB network determines crosslink interference between beams transmitted from a parent node and a child node, and generates commands to modify the beam properties, such as transmission power, to mitigate interference by adjusting the beam characteristics and reducing overlap between parent and child node communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If different link directions are multiplexed over the same frequency resources in IAB systems, then resource utilization efficiency is improved, but crosslink interference between parent and child nodes increases
Solution Approach 1:
The patent applies local quality by configuring different QCL (Quasi-Co-Location) assumptions for different DM-RS ports based on their specific interference characteristics. Specifically, the first DM-RS port uses a first QCL assumption while the second DM-RS port uses a second QCL assumption, allowing each port to be optimized for its local interference environment. This enables differentiated handling of interference in different spatial directions and frequency resources, thereby maintaining high resource utilization while mitigating crosslink interference through localized adaptation rather than uniform treatment across all resources.
2Reliability
If beam transmission power is increased to improve backhaul link reliability, then link reliability is improved, but interference to child node communications increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the QCL assumption parameters for different DM-RS ports based on measured interference conditions. The system monitors the interference level between parent and child nodes, and when interference exceeds a threshold, it modifies the QCL configuration parameters (such as spatial filter settings, reference signal associations) to change the beam characteristics. This allows the backhaul link to maintain sufficient power while altering the beam's spatial properties to reduce interference in the direction of child nodes, thereby resolving the contradiction between reliability and interference generation.
3Object-affected harmful factors
If beam properties are modified to reduce crosslink interference, then interference mitigation is improved, but beam transmission performance may deteriorate
Solution Approach 1:
The patent applies dynamics by implementing adaptive QCL configuration that continuously adjusts beam properties based on real-time interference measurements. The system dynamically switches between different QCL assumptions for the first and second DM-RS ports depending on the measured crosslink interference level. When interference is low, the system uses configurations optimized for transmission performance; when interference exceeds thresholds, it switches to configurations that prioritize interference mitigation. This dynamic adaptation ensures that beam transmission performance is maintained at optimal levels while effectively reducing crosslink interference when necessary.
Data Source
AI summary
A node of an Integrated Access and Backhaul (IAB) network comprises processor circuitry and interface circuitry. The processor circuitry is configured to make a determination concerning crosslink interference (CLI) between (a) a beam transmitted from a parent node to the IAB node and (b) a beam transmitted from the IBA node to a child node of the IAB node; and in accordance with the determination, and to generate a command configured to modify a property of the beam transmitted from the parent node to the IAB node. The interface circuitry is configured to transmit the command to a beam controller of the parent node.