Multi-RAT UE Link Setup With Preserved NR SCG Configuration

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Solution Overview

Problem

Existing multi-mode user equipment (UE) experiences high signaling load and delays in setting up and releasing Non-Standalone (NSA) 5G New Radio (NR) branches due to frequent NR secondary cell group (SCG) setup and release procedures, causing congestion in the anchor LTE network.

Innovation Solution

The UE stores default configuration information for NR communication and uses reduced-size LTE RRC messages combined with MAC-CE or DCI signaling to efficiently manage NR links, reducing redundant signaling and maintaining a preserved NR configuration context.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If frequent NR secondary cell group (SCG) setup and release procedures are implemented, then NR service availability is improved, but signaling load and network congestion increase

Engineering Contradiction:
ImproveNR service availabilityVSAvoidsignaling load
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The network pre-configures the UE with default NR SCG configuration information before actual NR connection is needed. This preliminary configuration includes default parameters and settings that can be quickly activated without full setup procedures, enabling rapid NR service deployment while minimizing signaling overhead during frequent connections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The UE stores and reuses previously received NR configuration information (default SCG config) for subsequent NR connections. Instead of receiving complete configuration messages each time, the UE copies and applies the stored default configuration, significantly reducing the quantity of signaling data required for frequent NR SCG setup operations.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If complete NR configuration messages are transmitted each time, then configuration accuracy is improved, but signaling delays increase

Engineering Contradiction:
Improveconfiguration accuracyVSAvoidsignaling delays
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The NR configuration information is segmented into default configuration parameters (transmitted once and stored) and specific connection parameters (transmitted on-demand). This segmentation allows the system to maintain configuration accuracy for critical parameters while reducing signaling delays by not retransmitting the entire configuration set for each connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Complete NR configuration messages are transmitted and stored in advance before actual NR service is required. The pre-transmitted default SCG configuration includes all necessary parameters for accurate NR setup, eliminating the need for time-consuming configuration transmissions during frequent NR connections.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If NR SCG release procedures are frequent, then network resource efficiency is improved, but LTE network congestion increases

Engineering Contradiction:
Improvenetwork resource efficiencyVSAvoidsignaling load
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The UE maintains a copy of the default NR SCG configuration in memory after initial reception. When releasing and re-establishing NR SCG connections, the UE reuses this stored configuration copy instead of requiring new configuration messages, reducing the signaling load generated by frequent release and setup procedures while maintaining network resource efficiency.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4114132B1Communications using multiple radio access technologies (RAT) for a multi-mode user equipment (UE)
Publication Date: 2026.02.25 APPLE INC
  • EP4114132B1 patent drawingFigure 1
  • EP4114132B1 patent drawingFigure 2
  • EP4114132B1 patent drawingFigure 3

AI summary

Some aspects of this disclosure relate to apparatuses and methods for communicating in a first radio access technology (RAT) and a second RAT. A user equipment (UE) can receive, from a first base station using the first RAT, first configuration information for the UE to communicate with a second base station via the second RAT; and receive, from the first base station using the first RAT, a downlink message to enable a communication link between the UE and the second base station via the second RAT. The downlink message includes second configuration information for the UE to communicate with the second base station via the second RAT. The UE can establish the communication link between the UE and the second base station using the second RAT based on a link configuration obtained from the first configuration information and the second configuration information.