RRC Resume Node Identification for Reliable UE Context Retrieval

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Solution Overview

Problem

Existing solutions fail to uniquely identify the source NG-RAN node from the Inactive Radio Network Temporary Identifier (I-RNTI) during the RRC Resume procedure in 5G networks, leading to difficulties in establishing a connection with the UE Context in the target node.

Innovation Solution

A method involving a first network node that maps its PLMN RAN Node ID to a Local RAN Node Identifier, which is sent to a second network node along with a UE Context ID, allowing the second node to retrieve the UE Context efficiently by using an Inactive Relation Table (IRT) to resolve the identity of the first node.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the I-RNTI is used to identify the source NG-RAN node during RRC Resume procedure, then the UE can be resumed from inactive state, but the source NG-RAN node cannot be uniquely identified by the target node

Engineering Contradiction:

ImproveUE Context retrieval reliabilityVSAvoidSource node identification information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The I-RNTI is segmented into multiple components: a first part containing the source gNB ID and a second part containing the UE Context ID. This segmentation allows the target gNB to extract the source node identifier from the I-RNTI, enabling unique identification of the source NG-RAN node while maintaining the UE Context retrieval functionality.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the full gNB ID is included in the I-RNTI, then the source node can be uniquely identified, but the I-RNTI length increases causing larger signaling overhead

Engineering Contradiction:

ImproveSource node identification precisionVSAvoidSignaling message size

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The source gNB ID is extracted from the full gNB ID configuration and embedded in the I-RNTI. This extraction allows the target gNB to identify the source node without transmitting the complete gNB ID, reducing signaling overhead while maintaining identification precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The I-RNTI structure is modified to include the source gNB ID as a specific parameter component. By changing the parameter composition of the I-RNTI to include identification information, the system achieves unique source node identification without requiring the full gNB ID length, optimizing the balance between identification precision and signaling efficiency.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260075676A1Network Nodes and Methods in a Radio Access Network for Improving the RRC Resume Procedure

Publication Date: 2026.03.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method performed by a first network node for assisting a second network node in resuming of a User Equipment (UE) in inactive state into connected state in a Radio Access Network (RAN). The first network node obtains (200) a Local RAN Node Identifier associated with a Public Land Mobile Network (PLMN) RAN Node ID, identifying the first network node. The first network node sends (201) the Local RAN node Identifier and associated PLMN RAN Node ID to be obtainable by the second network node. The first network node suspends (203) the UE from connected state into inactive state and sends an identifier to the UE. The identifier comprises a UE Context ID and the associated Local RAN Node Identifier. The UE Context ID identifies the UE context associated with the UE. The UE Context ID, Local RAN Node Identifier and associated PLMN RAN Node ID will assist the second network node to obtain the UE Context for the resuming of the UE into connected state, wherein a connection is to be provided by the second network node.