SRVCC Handover MSC Selection Reducing LAU Signaling

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Solution Overview

Problem

Frequent Location Area Updates (LAU) operations in Single Radio Voice Call Continuity (SRVCC) processing reduce system access success rates and cause signaling overheads in Home Location Register (HLR) systems during handovers between LTE and 2G/3G networks.

Innovation Solution

A method and apparatus that utilize a Mobility Management Entity (MME) or Serving General Packet Radio Service Support Node (SGSN) to determine if an associated Mobile Switching Center (MSC) with an SGs or Gs interface can perform SRVCC processing, thereby reducing LAU operations and signaling interactions with the HLR by using the MSC associated with the SGs or Gs interface for handover operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequent LAU operations are performed in SRVCC processing, then voice call continuity is maintained during handover, but system access success rate decreases and signaling overhead in HLR increases

Engineering Contradiction:
Improvevoice call continuityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent performs preliminary determination of whether the target cell belongs to the current MSC's location area before executing SRVCC handover. By checking the location area identity (LAI) against the current MSC's service area in advance, the system可以避免 unnecessary LAU operations, thereby reducing signaling overhead while maintaining voice call continuity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The MME/SGSN autonomously determines whether SRVCC handover requires LAU by comparing the target cell's LAI with the current MSC's location area. This self-service mechanism eliminates the need for additional LAU signaling to HLR when the target cell is within the same MSC's coverage, reducing signaling overhead without external intervention.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If frequent LAU operations are performed in SRVCC processing, then handover between networks is supported, but system access success rate decreases

Engineering Contradiction:
Improvehandover capabilityVSAvoidsystem access success rate
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary verification by comparing the target cell's location area identity with the current MSC's service area before initiating SRVCC handover. This advance check ensures that handover is only performed when necessary (i.e., when leaving the current MSC's location area), thereby maintaining handover capability while avoiding access failures caused by excessive LAU operations.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If SRVCC processing always selects MSC based on target identification information, then handover flexibility is maximized, but unnecessary LAU operations increase

Engineering Contradiction:
Improvehandover flexibilityVSAvoidsignaling interaction time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent introduces a preliminary check step that compares the target cell's LAI with the current MSC's location area before selecting a new MSC. When the target cell is within the current MSC's service area, the system maintains the existing MSC association, avoiding unnecessary LAU operations and reducing signaling interaction time while preserving handover flexibility for cases where MSC change is actually needed.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3001726B1Single radio voice call continuity operating method and device
Publication Date: 2020.03.25 HUAWEI TECH CO LTD
  • EP3001726B1 patent drawingFigure 1
  • EP3001726B1 patent drawingFigure 2
  • EP3001726B1 patent drawingFigure 3~4

AI summary

The present invention provides a single radio voice call continuity processing method and apparatus, where the method includes: when a single radio voice call continuity SRVCC processing handover request is received, determining, according to target identification information in the SRVCC handover request, whether to use a mobile switching center MSC, which is currently associated with an SGs interface or a Gs interface, as an SRVCC serving MSC; and when a result of determining is yes, performing SRVCC processing by using the MSC, which is currently associated with the SGs interface or the Gs interface, as the SRVCC serving MSC. According to the single radio voice call continuity processing method and apparatus in the embodiments, an MSC, which is currently associated with an SGs interface or a Gs interface, is used to execute an SRVCC handover operation for a UE, which can reduce LAU operations.