Intra-system Handoff Method Reducing eNodeB Configuration Complexity

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Solution Overview

Problem

The existing intra-system handoff methods in 3GPP wireless communication systems require complex configuration and coordination between eNodeBs, MMEs, and Serving GWs, leading to increased complexity and potential inconsistencies in network configurations, especially when handoffs occur between eNodeBs connected through the X2 interface.

Innovation Solution

The proposed intra-system handoff method involves a source base station requesting a handoff to a target base station, with the target base station determining access to the MME and, if necessary, reselecting a Serving GW to ensure seamless handoff, thereby simplifying the configuration process and maintaining consistent network connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the target eNodeB determines access to the Serving GW and configures bearer connections during handoff, then the handoff can be completed, but the configuration complexity at eNodeB increases and consistency between MME and eNodeB configurations becomes difficult to ensure

Engineering Contradiction:
Improvehandoff completionVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the Serving GW selection and bearer connection configuration functions from the eNodeB and relocates them to the MME. The eNodeB no longer needs to determine access to the Serving GW or configure bearer connections during handoff. Instead, the MME performs these functions centrally, eliminating the configuration complexity at eNodeB while ensuring consistency through centralized control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The MME acts as an intermediary that mediates between the eNodeB and the Serving GW. During handoff, the MME receives the handoff request from the source eNodeB, determines the target eNodeB's access to the Serving GW, and configures the bearer connections as needed. This intermediary role eliminates the need for eNodeB to directly manage Serving GW access and configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the eNodeB configures Serving GW access and bearer connections, then handoff can proceed, but the coordination between MME and eNodeB configurations becomes complex and error-prone

Engineering Contradiction:
Improvehandoff efficiencyVSAvoidcoordination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts the coordination functions for Serving GW access and bearer connection configuration from the eNodeB-MME interface and consolidates them within the MME. The MME independently determines Serving GW access and configures bearers without requiring complex coordination with eNodeB configurations, thereby simplifying the overall system architecture and reducing errors.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the target eNodeB performs Serving GW access determination and bearer configuration, then the handoff process can be completed, but the operational complexity at eNodeB increases

Engineering Contradiction:
Improvehandoff reliabilityVSAvoidoperational simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the operational tasks of determining Serving GW access and configuring bearer connections from the eNodeB and assigns them to the MME. The eNodeB simply initiates handoff by sending a handoff request to the target eNodeB, which then forwards the request to the MME. The MME performs the complex operational tasks centrally, making eNodeB operationally simple while maintaining handoff reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2086242B1An intra-system handoff method
Publication Date: 2016.04.13 ZTE CORP
  • EP2086242B1 patent drawingFigure 1
  • EP2086242B1 patent drawingFigure 2
  • EP2086242B1 patent drawingFigure 3A

AI summary

The present invention provides an intra-system handoff method, comprising the following steps: S302, when deciding a handoff of UE to a target base station, a source base station issues a handoff request to the target base station; S304, in response to the handoff request from the source base station, the target base station informs the source base station to conduct handoff for the UE; S306, after the completion of the handoff, the target base station issues an update request to an MME; and S308, in response to the update request from the target base station, the MME conducts Serving GW selection, and further fulfils the intra-system handoff. By the present invention, the target eNodeB need not determine whether access to the Serving GW is available, and accordingly the target eNodeB can avoid from configuring Serving GW