IAB Node Migration via Segmented MT and DU Functions
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Solution Overview
Problem
Current integrated access and backhaul (IAB) node systems face challenges in efficiently managing connections between different upstream nodes, particularly during high interference or load conditions, which can lead to disruptions in network connectivity and user experience.
Innovation Solution
An IAB node is equipped with a mobile termination (MT) function that receives indications to migrate from one upstream IAB donor node to another, performing random access procedures to establish new connections and trigger child node migrations, allowing seamless communication and network access without radio link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an IAB node maintains connection to a single upstream donor node, then the system structure is simple and easy to manage, but the network reliability deteriorates under high interference or load conditions
Solution Approach 1:
The IAB node is divided into multiple functional units: MT function for upstream communication, DU function for downstream communication, and multiple DU functions for serving different cell groups. This segmentation allows the node to independently manage connections to different donor nodes, improving reliability without overwhelming complexity
Solution Approach 2:
The IAB node is designed with multi-functionality to serve multiple upstream donor nodes simultaneously. The node can establish and maintain connections with different donor nodes through different cell groups, making it adaptable to varying network conditions and improving overall system reliability
2Reliability
If an IAB node performs handover between different donor nodes, then the network reliability improves, but the complexity of managing multiple cell groups and donor nodes increases
Solution Approach 1:
The IAB node performs preliminary actions by establishing multiple DU functions in advance, each associated with different cell groups and donor nodes. This preparation enables seamless handover without requiring complex real-time decision-making during migration
Solution Approach 2:
The control plane signaling acts as an intermediary that coordinates the handover process between donor nodes. The signaling manages the transition by coordinating between the source and target donor nodes, simplifying the overall handover management
3Productivity
If child nodes remain associated with the original cell group during parent node migration, then the parent node can migrate smoothly, but the user experience of child nodes deteriorates due to potential radio link failures
Solution Approach 1:
The parent IAB node performs preliminary actions by establishing a new DU function associated with the target donor node before triggering child node migration. This ensures that the child nodes have a valid target cell group ready, preventing radio link failures during the migration process
Solution Approach 2:
The system uses feedback mechanisms where the parent node monitors the establishment of new DU functions and triggers child node migration only when the new association is confirmed. This feedback loop ensures reliable migration without compromising child node connectivity
Data Source
AI summary
Aspects described herein relate to receiving, by a mobile termination (MT) function of an integrated access and backhaul (IAB) node, a first indication to migrate from a first IAB donor node associated with a first cell group and a first central unit (CU) to a second IAB donor node associated with a second cell group and a second CU, performing, by the IAB node and based at least in part on receiving the first indication, a first random access procedure to connect to the second cell group associated with the second IAB donor node, establishing, by the IAB node in addition to a first distributed unit (DU) function of the IAB node that serves a third cell group and based on performing the first random access procedure, a second DU function that serves a fourth cell group.