IAB Mobility Management for Accurate RNA Updates in Inactive Mode
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Solution Overview
Problem
In 5G NR networks, UEs connected via IAB nodes in inactive mode may erroneously trigger unwarranted RNA updates due to RNA definitions based on cell identities of RAN nodes, leading to unnecessary signaling and energy waste.
Innovation Solution
A method for RAN nodes to obtain IAB RNA association information, associate IAB relay nodes with the same RNA, and provide RNA information to UEs, while IAB relay nodes broadcast their cell identities and association with the RNA, ensuring seamless mobility management in inactive mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RNA is defined based on cell identities of RAN nodes, then the UE can determine RNA boundaries, but the UE coupled via IAB node may erroneously trigger unwarranted RNA updates
Solution Approach 1:
The patent introduces an intermediary mechanism by including IAB node identifiers in the RNA definition provided to the UE. This allows the UE to distinguish between cell identity changes that are part of the same RNA (when IAB nodes are involved) and actual RNA boundary crossings. The RAN node acts as a mediator that provides enhanced RNA information to the UE, enabling accurate RNA awareness despite IAB node mobility and cell identity changes.
2Loss of information
If the UE triggers RNA update upon detecting cell identity change, then the UE maintains RNA awareness, but unnecessary signaling and energy consumption occur
Solution Approach 1:
The patent applies preliminary action by providing the UE with RNA definition information that includes IAB node identifiers before the UE encounters mobility scenarios. This advance information allows the UE to pre-configure its RNA awareness logic, enabling it to distinguish between legitimate RNA boundary crossings and cell identity changes within the same RNA. As a result, the UE can avoid unnecessary RNA updates and the associated energy consumption while maintaining accurate RNA awareness.
3Adaptability or versatility
If IAB relay nodes are assigned new cell identities upon connecting to different RAN nodes, then the IAB nodes can be integrated into the network, but the UE erroneously assumes it has left the RNA
Solution Approach 1:
The patent extends the RNA definition from a single-dimensional cell identity list to a multi-dimensional structure that includes both cell identities and IAB node identifiers. This dimensional expansion allows the RNA definition to capture the hierarchical relationship between RAN nodes, IAB nodes, and cells. The UE can now evaluate RNA membership based on multiple dimensions, preventing erroneous RNA boundary detection when IAB nodes are involved while maintaining proper network integration flexibility.
Data Source
AI summary
The present disclosure relates to a method for use in a radio access network (RAN) node of a RAN of a cellular network. The RAN node connects integrated access and backhaul (IAB) relay nodes to the cellular network. The RAN node is associated with a RAN notification area (RNA) for mobility management of the wireless terminals operating in an inactive mode where a data connection between the respective wireless terminal and the RAN node is disconnected or suspended. The method comprises obtaining IAB RNA association information enabling the RAN node to prospectively associate IAB relay nodes that will newly connect to the RAN node with the same RNA as the RAN node, upon releasing a wireless terminal connected to the RAN node to the inactive mode, providing RNA information to the wireless terminal based on the previously obtained IAB RNA association information and upon an IAB relay node newly connecting to the RAN node, assigning a cell identity to the LAB relay node based on the previously obtained IAB RNA association information.