Paging Area Code Management for LEO Satellite Handoffs

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Solution Overview

Problem

Current satellite communication systems face challenges in managing paging areas, forbidden areas, and connection signaling effectively, particularly in non-geosynchronous satellite systems like LEO satellite-based systems, where user terminals (UTs) need to be handed off between satellites and may encounter service restrictions or access denial in certain locations.

Innovation Solution

The system employs a Paging Area Code (PAC) management system, using default PACs, reserved PACs, and forbidden PACs to handle UTs moving between satellites, entering or leaving forbidden areas, and managing connection releases, with mechanisms for UTs to request new PACs and reconfigure location reporting thresholds to ensure seamless service and efficient handoffs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a UT is handed off between satellites in a LEO satellite-based system, then communication coverage is maintained, but service disruptions may occur due to improper paging area management

Engineering Contradiction:
Improvecommunication continuityVSAvoidservice disruption time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by assigning a default paging area code to the UT before the handoff occurs. This default PAC is prepared in advance and stored in the UT, enabling immediate reconnection to the new satellite without waiting for paging area determination procedures during the handoff transition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The default paging area code acts as an intermediary element that bridges the transition between satellites. It provides a temporary but valid paging area identifier that allows the UT to maintain communication during the handoff process, mediating between the old and new satellite connections.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the system manages forbidden areas by rejecting connections, then service restrictions are enforced, but connection establishment failures occur

Engineering Contradiction:
Improveservice restriction enforcementVSAvoidconnection establishment success
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of immediately rejecting connections from forbidden areas, the system inverts the approach by first assigning a default paging area code and allowing the connection to be established. The forbidden area restriction is then enforced through subsequent paging area update procedures, separating connection establishment from restriction verification.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The connection management process is segmented into distinct phases: initial connection establishment using default PAC, and subsequent paging area update verification. This segmentation allows the system to separate the connection setup function from the forbidden area enforcement function, improving both reliability and adaptability.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If the system uses traditional paging area management, then service coverage is provided, but handoff efficiency decreases due to improper PAC assignment

Engineering Contradiction:
Improveservice coverage areaVSAvoidhandoff efficiency
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The system performs preliminary assignment of default paging area codes to UTs before handoff scenarios occur. This advance preparation ensures that UTs have valid PAC information ready, eliminating delays during handoff transitions and improving overall handoff efficiency while maintaining full service coverage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The paging area code assignment becomes dynamic, adapting to the UT's movement and handoff status. The system transitions from static PAC assignment to dynamic default PAC assignment, allowing the PAC to be automatically updated and reassigned based on the UT's current satellite connection and location, thereby improving handoff efficiency.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3530035B1Forbidden area procedures and connection release management
Publication Date: 2021.11.17 QUALCOMM INC
  • EP3530035B1 patent drawingFigure 1
  • EP3530035B1 patent drawingFigure 2
  • EP3530035B1 patent drawingFigure 3

AI summary

The disclosure relates in some aspects to forbidden area procedures and connection release management for a user terminal (UT). Forbidden area-related procedures include, for example, using a special paging area code (PAC) in conjunction with a forbidden area, defining a location reporting threshold for a UT based on the proximity of the UT to a forbidden area, or using a default paging area code if a service restriction for a UT has ended. Connection release management includes, for example, a UT sending a request to cause the release of a Radio Connection that the UT no longer needs, or a UT sending a Location Indication (e.g., including a flag requesting release of a connection) to release the connection used for location reporting when a UT is done sending the location information and is going to go back to idle mode.