Non-Terrestrial Network Handover Without Random Access

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Solution Overview

Problem

Non-terrestrial networks (NTN) face challenges with high signaling overhead and energy consumption due to large cell sizes and predictable satellite movements, requiring many devices to perform handovers simultaneously, especially for IoT devices.

Innovation Solution

A method where user equipment determines a mobility indicator based on its relative velocity with respect to the base station, transmitting this indicator to facilitate handover without a random access procedure when the velocity is below a threshold, allowing stationary or low-mobility UEs to resume operations using previously granted resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If handover procedure is performed for all UEs in NTN networks, then service continuity is maintained, but signaling overhead and energy consumption increase significantly

Engineering Contradiction:

Improveservice continuityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by differentiating handover procedures based on UE mobility characteristics. Stationary or low-mobility UEs follow a simplified handover procedure that maintains service continuity without requiring full random access procedure, while mobile UEs undergo complete handover. This localized differentiation reduces overall signaling overhead and energy consumption while preserving reliability for affected UEs.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the handover procedure into two distinct types: simplified handover for stationary/low-mobility UEs and complete handover for mobile UEs. This segmentation allows the network to handle different UE categories with appropriate procedures, reducing unnecessary signaling overhead and energy consumption for UEs that do not require full handover processing.

Inventive Principle:

Principle #1Segmentation

2Reliability

If handover procedure is performed for all UEs in NTN networks, then service continuity is maintained, but signaling overhead increases significantly

Engineering Contradiction:

Improveservice continuityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the handover procedure into two distinct types: simplified handover for stationary/low-mobility UEs and complete handover for mobile UEs. This segmentation allows the network to handle different UE categories with appropriate procedures, reducing unnecessary signaling overhead and complexity for UEs that do not require full handover processing.

Inventive Principle:

Principle #1Segmentation

3Reliability

If random access procedure is required for all handovers, then connection is established reliably, but energy consumption and time increase

Engineering Contradiction:

Improveconnection reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-configuring uplink resources for stationary or low-mobility UEs before handover occurs. The target base station is provided with uplink resource configuration information from the source base station, allowing the UE to resume transmission using pre-established resources without performing random access procedure. This preliminary preparation maintains connection reliability while significantly reducing energy consumption and handover time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by allowing stationary or low-mobility UEs to autonomously resume transmission using previously granted uplink resources without requiring network intervention through random access procedure. The UE independently utilizes the pre-configured resources, eliminating the energy-intensive random access process while maintaining reliable connection through the simplified handover mechanism.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20250287268A1System, methods, user equipment and base stations for wireless communication in a non-terrestrial network

Publication Date: 2025.09.11 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH

AI summary

In a handover process in non-terrestrial networks, a user equipment determines a mobility indicator representative of whether a relative velocity between the user equipment device and a serving base station is lower than a threshold, transmits the mobility indicator to the serving first base station, and completes handover to a second base station without random access procedure when the relative velocity is lower than the threshold.