Handover Location Continuity via Target Node Identity Transfer

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Solution Overview

Problem

Existing wireless communication networks face challenges in maintaining location continuity for user equipment (UE) during handovers between different radio access networks, especially during emergency calls, as existing solutions fail to ensure seamless location service support across network transitions.

Innovation Solution

The proposed solution involves transferring the identity of the target serving node to the target location server during handover, allowing the Location and Routing Function (LRF) to initiate and maintain location sessions, and potentially removing the source location server if it differs from the target server, ensuring continuous location services across network transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE is handed over from one wireless network to another during a call, then the communication service continuity is maintained, but the location service continuity is lost

Engineering Contradiction:
Improvelocation service continuityVSAvoidnetwork handover capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The target serving node proactively provides its identity to the target location server before the handover is complete, enabling the location server to prepare for maintaining location services. This preliminary action ensures that when the handover occurs, the location service continuity is already established rather than being reactive to the handover event.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The LRF acts as an intermediary between the serving nodes and location servers, receiving identity information from the target serving node and coordinating with both source and target location servers. This intermediary function enables seamless transition of location services during handover by managing the interactions between different network elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the source location server is removed after handover, then the location service accuracy is improved, but the service interruption risk increases

Engineering Contradiction:
Improvelocation estimate accuracyVSAvoidservice continuity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The target location server is provided with the target serving node identity before the source location server is removed, allowing the location estimation process to be seamlessly transferred. This preliminary setup ensures that when the source server is removed, the target server is already prepared to take over without causing service interruption or reducing accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the LRF monitors the handover process and coordinates the removal of the source location server only after confirming that the target location server is ready and capable of providing accurate location estimates. This feedback loop ensures that accuracy is maintained while managing the transition safely.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2394447B1Maintaining location continuity for a UE following handover
Publication Date: 2019.10.23 QUALCOMM INC
  • EP2394447B1 patent drawingFigure 1
  • EP2394447B1 patent drawingFigure 2
  • EP2394447B1 patent drawingFigure 3

AI summary

Techniques for maintaining location continuity for a user equipment (UE) following handover are described. The UE communicates with a first radio access network (RAN) and is served by a source serving node and a source location server prior to handover. The UE communicates with a second RAN and is served by a target serving node and a target location server after the handover. In an aspect, location continuity may be maintained for the UE by transferring an identity of the target serving node to a location server during handover of the UE. In one design, the target serving node sends its identity to the target location server, which updates a Location and Routing Function (LRF) serving the UE. In another design, for handover from packet- switched domain to circuit-switched domain, the source serving node sends the target serving node identity to the source location server, which updates the LRF.