Network Node Handover Delaying Dedicated Bearer Setup

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Solution Overview

Problem

Current methods for handover of communication services from Circuit Switched (CS) to Packet Switched (PS) networks, such as during SRVCC, often result in degraded user service quality due to high bit rate errors and increased complexity in network signaling, particularly impacting the SGSN and MSC nodes.

Innovation Solution

A method where the network node delays the setup of a dedicated bearer in the PS network until the handover from the CS network is complete, allowing media to be sent on a default bearer, thereby minimizing disruptions and reducing the impact on network nodes like the SGSN and MSC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If immediate dedicated bearer setup is performed in PS network during CS to PS handover, then service continuity is maintained, but user service quality degrades due to high bit rate errors and call drops

Engineering Contradiction:
Improveservice continuityVSAvoiduser service quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The network node prepares the dedicated bearer setup in advance during the handover process, but delays the actual activation until after the handover is complete. This preliminary preparation ensures that the bearer is ready to be activated immediately when needed, maintaining service continuity while avoiding quality degradation during the handover transition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a buffering mechanism where media packets are temporarily stored during the handover transition period. This cushioning approach prevents data loss and bit rate errors that would otherwise occur during the transition from CS to PS network, thereby maintaining user service quality while ensuring seamless handover.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If dedicated bearer setup is delayed until handover completion, then user service quality improves and call drops are reduced, but handover complexity increases

Engineering Contradiction:
Improveuser service qualityVSAvoidhandover process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The network node automatically manages the bearer setup timing based on handover status detection. The system self-adjusts when to activate the dedicated bearer by monitoring handover completion indicators, eliminating the need for complex external coordination mechanisms and reducing overall handover process complexity while maintaining service quality.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where the network node receives handover completion status information and automatically adjusts the bearer activation timing accordingly. This feedback-driven approach simplifies the control logic by using clear status indicators to trigger appropriate actions, reducing handover complexity while ensuring optimal service quality.

Inventive Principle:
Principle #23Feedback

3Speed

If immediate dedicated bearer setup is performed, then handover speed is maintained, but network signaling complexity and node impact increase

Engineering Contradiction:
Improvehandover speedVSAvoidnetwork signaling complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent extracts the bearer setup activation step from the immediate handover execution sequence and separates it into a post-handover operation. This extraction allows the handover to complete quickly without the overhead of simultaneous bearer setup signaling, reducing network signaling complexity while maintaining handover speed through asynchronous execution.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2730127B1Method and device for handling handover of a communications service
Publication Date: 2015.04.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2730127B1 patent drawingFigure 1
  • EP2730127B1 patent drawingFigure 2
  • EP2730127B1 patent drawingFigure 3

AI summary

The embodiments herein relate to a method in a network node for enabling handover of a communications service from a circuit switched, referred to as CS, network (100a) to a packet switched, referred to as PS, network (100b), wherein a user equipment (101) is located in the CS network (100a) and having the communications service in the CS network (100a).