Handover Management Between Terrestrial and Non-Terrestrial Networks

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Solution Overview

Problem

Existing technologies face challenges in ensuring seamless service continuity for User Terminals (UTs) during handovers between Terrestrial Networks (TN) and Non-Terrestrial Networks (NTN), leading to potential service disruptions and hysteresis issues.

Innovation Solution

A system and method that utilize a computer-readable storage medium with instructions to manage handovers between TN and NTN by determining when a UT is leaving a coverage area, disconnecting from the first network, and establishing communication with the second network without interruption, using measurement configurations and reports to prevent service gaps and hysteresis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If handover procedures are implemented between TN and NTN, then service continuity is improved, but hysteresis issues and service disruptions occur

Engineering Contradiction:

Improveservice continuityVSAvoidservice disruption time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs measurement configurations and measurements in advance before handover is needed. The network configures the UT to perform measurements on both TN and NTN networks, and the UT reports measurement results proactively, enabling the network to prepare handover parameters before service disruption occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements continuous measurement reporting where the UT provides feedback to the network about signal quality and coverage conditions. This feedback loop enables the network to make informed handover decisions based on real-time conditions, preventing service disruptions by triggering handover before complete signal loss occurs.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If measurement configurations are performed continuously, then handover timing precision is improved, but network overhead and complexity increase

Engineering Contradiction:

Improvehandover timing precisionVSAvoidnetwork overhead

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of continuous measurements, the system implements periodic measurement configurations where the UT performs measurements at scheduled intervals. This reduces network overhead and processing complexity while maintaining sufficient precision for handover decisions by capturing signal quality trends over time.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP3800936B1Handover in connected mode between non-terrestrial-network and terrestrial network

Publication Date: 2023.07.05 HUGHES NETWORK SYST

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AI summary

A system and a method for directing a handover of communications in Radio Frequency (RF) networks at a UT. The method includes servicing a user terminal (UT) via a first network having a first coverage area; receiving, from the UT via the first network, a measurement report for a second network having a second coverage area based on a measurement configuration of the second network; sending, to the UT via the first network, a handover order for obtaining service from the second network; and establishing, via a second network RAN (radio access network), a service for the UT via the second network per the handover order. In the method, the first network may include either a terrestrial network (TN) or a non-terrestrial network (NTN), the second network may include other of the TN or the NTN, and the TN and the NTN are RF networks. In the method, the establishing is performed while the UT is disposed in an overlap area of the first coverage area and the second coverage area, and the measurement report may include a RF signal metric of the second network at the UT.