E-RAB Switch Failure Handling in Dual Connectivity

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Solution Overview

Problem

In wireless communication systems, particularly in LTE networks, E-UTRAN radio access bearer (E-RAB) switch failures occur during dual connectivity, leading to operational challenges with existing methods being unclear on how to handle such failures effectively.

Innovation Solution

A method and apparatus that receive an E-RAB modification confirm message, including a list of failed E-RABs, keep the old transport path, and trigger a secondary evolved NodeB (SeNB) release procedure to manage E-RAB switch failures efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If E-RAB modification is attempted during SeNB addition or modification in dual connectivity, then network resources can be optimized and service quality improved, but E-RAB switch failure may occur leading to connection instability

Engineering Contradiction:
ImproveE-RAB connection stabilityVSAvoidE-RAB modification capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by maintaining the old transport path for failed E-RABs before switching to new paths. This ensures that if E-RAB modification fails during SeNB addition or modification, the original connection remains intact and functional, preventing service interruption while allowing retry or fallback mechanisms to operate.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes by modifying the E-RAB configuration state through maintaining old transport paths. This state change allows the system to transition from a vulnerable state (where failed modification would break connection) to a protected state (where old path serves as backup), enabling safe parameter updates during dual connectivity operations.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If E-RABs are released when modification fails, then network resources are freed for reallocation, but service continuity is disrupted and user experience deteriorates

Engineering Contradiction:
ImproveNetwork resource utilizationVSAvoidService continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by maintaining old transport paths as a protective buffer when E-RAB modification fails. This cushioning mechanism ensures that even if modification fails, the old path continues to carry traffic, preventing service disruption. Resources are only released after confirming the new path is fully functional, thus protecting service continuity while enabling resource optimization.

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

3Reliability

If E-RABs are kept with old GTP tunnel after failed modification, then service continuity is maintained, but network resources are wasted and system efficiency decreases

Engineering Contradiction:
ImproveService continuityVSAvoidNetwork resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements feedback mechanisms by monitoring E-RAB modification outcomes and using this information to determine resource management actions. When modification fails, the system feedback indicates to maintain old transport paths. When modification succeeds, feedback triggers release of old resources. This feedback-driven approach ensures service continuity during failures while preventing resource waste upon successful transitions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making the transport path configuration flexible and adaptive based on modification outcomes. The system dynamically transitions between using old and new transport paths depending on whether modification succeeds or fails, allowing optimal resource utilization while maintaining service continuity. This dynamic behavior eliminates static resource allocation inefficiencies.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3207740B1Method and apparatus for handling gateway e-RAB switch failures in dual connectivity
Publication Date: 2020.09.30 LG ELECTRONICS INC
  • EP3207740B1 patent drawingFigure 1
  • EP3207740B1 patent drawingFigure 2
  • EP3207740B1 patent drawingFigure 3~5

AI summary

A method and apparatus for handling evolved universal terrestrial radio access network (E-UTRAN) radio access bearer (E-RAB) switch failure for dual connectivity in a wireless communication system is provided. A master evolved NodeB (MeNB) in dual connectivity receives an E-RAB modification confirm message including a list of E-RABs failed to be modified from a mobility management entity (MME). The MeNB may keep old general packet ratio service (GPRS) tunneling protocol (GTP) tunnels for the failed E-RABs, and trigger a secondary eNB (SeNB) release procedure or a SeNB modification procedure for releasing the failed E-RABs. Alternatively, the MeNB may trigger an E-RAB release procedure for releasing the failed E-RABs.