Relay Station Handover Interface Selection

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Solution Overview

Problem

In LTE-A communication systems, the inability to properly determine whether to use an X2 interface or an S1 interface for handover can lead to handover failures due to the relay station's lack of information about the mobility management entity pool affiliation of neighboring eNBs, resulting in incorrect handover procedures.

Innovation Solution

A method and device where a relay station obtains information to determine if the mobility management entity of a user equipment is in the same pool as the neighboring eNB, and if not, determines that the X2 interface cannot be used for handover, thereby initiating a correct handover procedure by using an S1 interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the relay station uses the X2 interface for handover without verifying MME pool affiliation, then the handover procedure can be initiated quickly, but handover failure occurs when the MME is not in the same pool as the neighboring eNB

Engineering Contradiction:
Improvehandover initiation speedVSAvoidhandover success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The relay station performs preliminary verification of MME pool affiliation before initiating the handover procedure. By checking whether the MME of the user equipment belongs to the same pool as the neighboring eNB in advance, the system prevents initiating handover via X2 interface when pool affiliation mismatch is detected, thereby avoiding handover failure while maintaining efficient handover initiation when conditions are satisfied

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanism where the relay station obtains MME pool affiliation information and uses this feedback to determine the appropriate handover interface. The handover decision is adjusted based on the feedback regarding MME pool membership, ensuring that handover is only initiated through X2 interface when the MME and neighboring eNB belong to the same pool, thus improving handover reliability

Inventive Principle:
Principle #23Feedback

2Reliability

If the relay station obtains and verifies MME pool affiliation information before handover, then handover success rate improves, but the handover procedure becomes more complex

Engineering Contradiction:
Improvehandover success rateVSAvoidhandover procedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the MME pool affiliation verification step as a separate, independent check from the main handover procedure. By isolating this verification process, the system adds minimal complexity only where necessary (in the decision logic) while keeping the actual handover execution procedures unchanged, thus improving reliability without significantly increasing overall system complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system changes the decision parameter for handover interface selection from a simple interface availability check to a composite parameter that includes MME pool affiliation status. This parameter change enables more accurate handover decisions (improving success rate) while the complexity increase is limited to the decision-making logic rather than the execution mechanisms

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2712233B1Handover processing method and device
Publication Date: 2015.12.23 HUAWEI TECH CO LTD
  • EP2712233B1 patent drawingFigure 1~2
  • EP2712233B1 patent drawingFigure 3a
  • EP2712233B1 patent drawingFigure 3b

AI summary

A handover processing method and device are provided, and belong to the field of communications technologies. The method may include: obtaining, by a relay station, information, where the information is used for determining whether a mobility management entity (MME) of a user equipment is in a mobility management entity pool (MME pool) to which a neighboring eNB belongs; and determining, by the relay station, that an X2 interface between a serving eNB of the relay station and the neighboring eNB cannot be used for handover if the MME of the user equipment is not in the MME pool to which the neighboring eNB belongs. The foregoing technical solutions may enable the relay station to initiate a correct handover procedure.