Target RAN Node Slice Signaling for Inter-RAT Handover

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Solution Overview

Problem

Existing handover procedures from LTE to 5G networks fail to consider the network slice to which a UE should be connected during the handover, leading to inadequate configuration of the Access Stratum (AS) and Non-Access Stratum (NAS) layers.

Innovation Solution

Involves a target radio access network node receiving slice information from the core network and creating radio resource configuration information for the UE, which is then transmitted to the UE during handover, ensuring appropriate configuration of the AS and NAS layers in the target network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If existing handover procedures from LTE to 5G networks are used, then the handover process is simple and fast, but the AS and NAS layers are inadequately configured for network slicing requirements

Engineering Contradiction:

Improveconfiguration precisionVSAvoidhandover procedure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The target RAN node receives slice information from the core network before completing the handover procedure. This preliminary receipt of slice information enables the target node to prepare appropriate AS and NAS layer configurations in advance, ensuring that when the UE completes handover, the network is already ready to provide slice-specific services without requiring complex post-handover reconfiguration procedures

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The core network acts as an intermediary by providing slice information to the target RAN node during the handover procedure. This intermediary mechanism allows the source LTE network and target 5G network to coordinate the handover with proper slice awareness, enabling precise configuration without significantly increasing the complexity of the handover procedure itself

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If slice information is received and processed during handover, then appropriate AS and NAS layer configuration is achieved, but the handover procedure becomes more complex

Engineering Contradiction:

Improvenetwork slice adaptabilityVSAvoidhandover operation ease

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The target RAN node is designed with multi-functionality to handle both traditional handover procedures and slice-aware handover procedures through a unified interface. By integrating slice information processing into the existing handover workflow, the system maintains ease of operation for standard handovers while gaining the adaptability to handle network slicing requirements when slice information is provided, without requiring separate complex procedures

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12432568B2Radio access network node, radio terminal, core network node, and method therefor

Publication Date: 2025.09.30 NEC CORP

AI summary

During handover of a radio terminal (1) from a first network to a second network, a target RAN node (3) is operates to: receive, from a core network (5), slice information about a network slice which is included in the second network and to which the radio terminal (1) is to be connected; create, upon receiving the slice information, radio resource configuration information that is to be used by the radio terminal (1) after the handover in the second network; and transmit this radio resource configuration information through the first network to the radio terminal (1). It is possible to contribute to appropriately configuring an AS layer or NAS layer of a target RAT in inter-RAT handover.