MME Bearer Status Update for LTE Handover Scheduling

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Solution Overview

Problem

During handover in LTE systems, the target eNB may only accept part of the bearers, leading to inaccurate scheduling and adverse impact on transmission performance due to the use of unchanged UE-AMBR values from the source side, which do not reflect the actual bearer connection conditions.

Innovation Solution

The MME obtains bearer information accepted by the target eNB and updates the UE-AMBR accordingly, ensuring resource scheduling is based on practical connection conditions by determining which bearers are maintained after handover and adjusting the UE-AMBR values accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the target eNB uses the same UE-AMBR value as the source eNB during handover, then the handover procedure is simple and fast, but the resource scheduling becomes inaccurate and transmission performance deteriorates

Engineering Contradiction:

Improvehandover speedVSAvoidscheduling accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The source eNB performs preliminary actions by determining the UE-AMBR value based on bearer connection conditions before handover and includes it in the handover request message sent to the target eNB. This allows the target eNB to have the correct UE-AMBR value ready in advance, ensuring both fast handover and accurate scheduling without needing to recalculate after handover.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the target eNB accepts only part of the bearers during handover, then resource allocation becomes more flexible and efficient, but the UE-AMBR value becomes outdated and causes scheduling errors

Engineering Contradiction:

Improveresource allocation flexibilityVSAvoidscheduling reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The target eNB sends feedback information to the source eNB about which bearers are accepted and which are rejected during handover. The source eNB uses this feedback to recalculate the UE-AMBR value based on the actual bearer connection conditions at the target side, and sends the updated UE-AMBR to the target eNB. This feedback mechanism ensures the UE-AMBR always reflects the current bearer status, maintaining scheduling reliability while allowing flexible resource allocation.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP2306772B1Method and mobility management entity for acquiring bearer status at the time of user equipment switching

Publication Date: 2015.02.25 CHINA ACAD OF TELECOMM TECH

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AI summary

The present invention provides a method for obtaining bearer condition during a handover of UE. The method includes: making an admission control, by a target eNB, for a UE based on received bearer information of the UE during handover of the UE, determining the at least one accepted bearer, and informing a MME of the at least one accepted bearer; updating, by the MME, a UE-AMBR used by the target eNB based on the received at least one accepted bearer. The present invention also provides an MME which enables the target side obtain actual bearer condition during handover of a UE.