Signaling RedCap UE Identification in Inter-RAT Handover

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Solution Overview

Problem

Current inter-Radio Access Technology (RAT) handover mechanisms do not effectively support the identification and signaling of Reduced Capability (RedCap) wireless communication devices, particularly during handovers from Evolved Packet System (EPS) to 5th Generation System (5GS), leading to challenges in policy and charging control.

Innovation Solution

Incorporating new NR RedCap indications into inter-RAT handover messages, such as the NG-AP HANDOVER REQUEST ACKNOWLEDGE and PATH SWITCH REQUEST messages, to signal the target network node about the RedCap UE capabilities, allowing the 5GC to recognize and manage RedCap UEs appropriately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inter-RAT handover mechanisms are used, then handover procedures are simple and fast, but RedCap UE identification and signaling are not supported

Engineering Contradiction:

ImproveRedCap UE identification accuracyVSAvoidhandover signaling complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by including RedCap indication information in the source-to-target transparent container during handover preparation, before the actual handover execution. This allows the target gNB to be pre-informed about the UE's RedCap status, enabling proper resource allocation and policy application without delaying the handover process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the source-to-target transparent container as an intermediary to transfer RedCap indication information from the source eNB to the target gNB. This intermediary mechanism enables indirect signaling of RedCap status without requiring direct communication between UEs and target nodes, maintaining the existing handover architecture while adding RedCap support.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If RedCap indication is added to handover messages, then RedCap UE management is improved, but message size and processing overhead increase

Engineering Contradiction:

ImproveRedCap UE policy control accuracyVSAvoidhandover message size

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges the RedCap indication information with the existing source-to-target transparent container that is already part of the handover procedure. By combining RedCap signaling with an existing message structure rather than creating a separate message, the patent avoids significant increases in message size and processing overhead while still achieving reliable RedCap UE identification and policy control.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20240414600A1Signaling for inter-rat handover of redcap ues

Publication Date: 2024.12.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Systems and methods are disclosed for signaling Reduced Capability (RedCap) wireless communication device (WCD) capability during inter-Radio Access Technology (RAT) handover. In one embodiment, a method performed by a target network node for inter-RAT handover of a WCD from a source network node of a first RAT to the target network node of a second RAT comprises receiving, at the target network node, a message in association with preparation or execution of a handover of a WCD from the source network node of the first RAT to the target network node of the second RAT, the message comprising information about one or more capabilities of the WCD. The method further comprises determining that the WCD is a RedCap WCD based on the information about the one or more capabilities of the WCD and sending an indication that the WCD is a RedCap WCD to a core network node.