Local Switch Handover via Core Network Indication

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Solution Overview

Problem

In GSM systems, handovers during local switches result in delays and resource losses due to the inability of the BSS to accurately determine valid user-plane links, leading to inefficient handover processes.

Innovation Solution

A method and system where the core network provides indication information to the source BSS to determine whether to transmit user-plane speech data from the MGW or an internal link during handovers, using mute and non-mute frames to indicate link validity, allowing the BSS to directly perform handovers without resource loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the local switch function is used to switch voice data within BSS, then transmission resource loss is reduced, but handover cannot be performed when a terminal needs to move between BSCs

Engineering Contradiction:
Improvetransmission resource lossVSAvoidhandover capability
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent segments the user-plane speech data transmission path by introducing indication information that separates the control signaling (from core network) from the actual speech data transmission (through local switch or via MGW). This allows the system to maintain local switch functionality while enabling handover through proper routing based on the indication information.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces indication information as an intermediary mechanism that mediates between the core network and the BSS. This indication information acts as a controller that directs the BSS on whether to transmit speech data received from MGW or from the internal local switch link, enabling flexible handover while maintaining local switch efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the existing handover method is used (stopping local switch, restoring core network switching, then performing handover), then handover can be completed, but handover time is delayed and transmission resources are lost

Engineering Contradiction:
Improvehandover completionVSAvoidhandover time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the core network send indication information to the source BSS before the handover actually occurs. This indication information pre-configures the BSS on how to handle speech data transmission during the upcoming handover, eliminating the need to stop the local switch function and restore core network switching beforehand.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuity of useful action by allowing the local switch function to remain active during handover. The BSS continuously transmits speech data according to the indication information received from the core network, whether from the internal local switch link or from the MGW, without interrupting the local switch operation.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If the BSS transmits user-plane speech data during handover without indication information, then transmission continues, but the BSS cannot determine which link is valid causing incorrect data transmission

Engineering Contradiction:
Improvetransmission continuityVSAvoidlink validity determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by having the core network send indication information to the BSS that provides real-time guidance on which transmission link is valid. This feedback mechanism allows the BSS to accurately determine whether to transmit speech data from the internal local switch link or from the MGW, ensuring correct data transmission during handover while maintaining continuous productivity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2536215B1System, method and base station subsystem for realizing handover in local switch
Publication Date: 2016.04.13 ZTE CORP
  • EP2536215B1 patent drawingFigure 1~2
  • EP2536215B1 patent drawingFigure 3
  • EP2536215B1 patent drawingFigure 4

AI summary

The present invention discloses a method for implementing a handover in a local switch, and the method includes: a core network transmitting indication information to a source base station subsystem during any terminal of communication parties which carries out a local switch is performing a base station subsystem handover, and the source base station subsystem determining whether to transmit user-plane speech data received from a media gateway to the terminal which has not performed the base station subsystem handover, or to transmit the user-plane speech data received from an internal link to the terminal which has not performed the base station subsystem handover, according to the indication information. The present invention also discloses a system for implementing a handover in a local switch as well as a base station subsystem. The present invention can accomplish the base station subsystem (BSS) handover of terminals while realizing a local switch, thus effectively avoiding the loss of speech data.