PCI Coordination in IAB Networks to Prevent Collisions
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Solution Overview
Problem
In wireless communication systems, the reconfiguration of physical cell identifiers (PCIs) by different central units can lead to increased interference and a higher likelihood of PCI collisions and UE handover failures during cell migrations, especially when cells share the same carrier.
Innovation Solution
A method where a distributed network node associated with an integrated access and backhaul node transmits a restriction indication to a central network node, which then configures the PCI of the cell accordingly, ensuring that specific PCI values are not used to prevent collisions and optimize handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different central units reconfigure PCI independently for their associated cells, then each CU can optimize its cell configuration, but PCI collisions and interference increase when cells share the same carrier
Solution Approach 1:
A PCI coordination entity is introduced as an intermediary between central units to manage PCI allocation. This mediator receives PCI requests from multiple CUs, coordinates the assignment to avoid conflicts, and ensures that cells sharing the same carrier receive unique PCIs, thereby resolving the contradiction between independent configuration flexibility and collision avoidance
Solution Approach 2:
The system implements feedback mechanisms where CUs report their current PCI configurations and cell status to the coordination entity. Based on this feedback, the coordinator adjusts PCI assignments dynamically to prevent collisions while maintaining configuration flexibility, and notifies CUs of any changes required
2Productivity
If PCI is reconfigured during cell migration, then network optimization is achieved, but UE handover failure likelihood increases
Solution Approach 1:
The coordination entity performs preliminary PCI assignment and validation before cell migration is executed. By pre-coordinating PCI configurations and ensuring no conflicts exist before handover begins, the system enables network optimization while preventing handover failures that would result from PCI collisions during the migration process
Solution Approach 2:
The system establishes PCI conflict prevention mechanisms in advance of cell migration events. The coordination entity maintains a global view of PCI usage and prepares conflict-free PCI assignments before migration occurs, cushioning against potential handover failures that would otherwise result from uncoordinated PCI reconfiguration
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a distributed unit (DU) associated with an integrated access and backhaul (IAB)-node may transmit, and a central unit (CU) may receive, a restriction indication that indicates a restriction for a physical cell identifier (PCI) configuration of a cell that is served by the DU. The restriction indication may include, for example, one or more PCI values that are not to be used for the PCI configuration of the cell, and/or may include one or more PCI values that are allowed to be used for the PCI configuration of the cell. The CU may transmit, and the DU may receive, a PCI configuration of the cell that is in accordance with the restriction indication. Numerous other aspects are described.