Terminal Mobility Management for NGSO Satellite Networks

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Solution Overview

Problem

In the context of space-earth integration networks, particularly for Beyond 5G and 6G mobile communications, existing mobility management technologies face challenges in accurately locating multi-connection User Equipment (UE) in low earth orbit satellite networks due to the large beam size of satellites, which leads to inefficiencies in position updates and increased signaling overhead.

Innovation Solution

A mobility management method and device that utilize local storage and dynamic updates of communication calendars, including NGSO satellite ephemeris and terrestrial communication calendars, to simplify the process of establishing communication connections with NGSO satellites, reduce signaling overhead, and improve position update efficiency by allowing terminals to select optimal satellite connections based on performance evaluation values without requiring real-time signal measurement or network control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal establishes connections with multiple satellites simultaneously and determines target satellite switching by measuring signal strength, then the mobility management can be performed, but the signaling overhead increases and the position update efficiency decreases

Engineering Contradiction:
Improvemobility managementVSAvoidposition update efficiency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The terminal pre-calculates satellite switching time points and target satellites by querying the communication calendar and comparing satellite ephemeris data, rather than waiting for network paging or performing real-time signal measurement. This preliminary action eliminates the need for continuous signal strength measurement and reduces position update delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The terminal autonomously determines satellite switching by comparing its own position (obtained from GEO satellites) with satellite ephemeris data in the communication calendar, without requiring network control or signal measurement feedback. This self-service approach reduces signaling overhead and improves position update efficiency.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the terminal establishes connections with multiple satellites simultaneously, then the satellite switching can be performed, but the signaling overhead increases

Engineering Contradiction:
Improvesatellite switchingVSAvoidsignaling overhead
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The terminal independently determines satellite switching by comparing its position with satellite ephemeris data, eliminating the need for network-controlled switching procedures. This self-service mechanism maintains satellite switching capability while significantly reducing uplink signaling overhead for switching requests and measurements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the satellite switching decision-making function from the network control plane and relocates it to the terminal's local processing unit. By taking out the switching decision function from network control, the system reduces signaling overhead while maintaining adaptability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the network pages the terminal to update position information, then the position can be updated, but the signaling overhead increases and the position accuracy decreases due to large satellite beam size

Engineering Contradiction:
Improveposition accuracyVSAvoidsignaling overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The terminal autonomously updates its position information by comparing its own position (from GEO satellites) with the satellite ephemeris data in the communication calendar, eliminating the need for network paging. This self-service position update mechanism improves accuracy by using precise ephemeris data while reducing signaling overhead.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The terminal pre-queries the communication calendar to obtain satellite ephemeris data and pre-calculates position information, rather than waiting for network paging. This preliminary action enables accurate position tracking without the overhead of continuous network paging.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4167624B1Mobility management method and device
Publication Date: 2024.11.20 CHINA MOBILE COMM GRP CO LTD
  • EP4167624B1 patent drawingFigure 1
  • EP4167624B1 patent drawingFigure 2A
  • EP4167624B1 patent drawingFigure 2B

AI summary

A mobility management method and device. The method comprises: obtain a terminal a first position of a terminal from a geo-synchronous orbit (GEO) positioning satellite; the terminal searches for a first communication calendar according to the first position, and determines a network connection mode of the terminal; when it is determined that the network connection mode is an NGSO satellite connection, the terminal accesses a network by means of a first NGSO satellite and sends, by means of the first NGSO satellite, a first request message carrying the first position to the network.