Macro NodeB Load Balancing via Target Home NodeB Information Acquisition

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Solution Overview

Problem

In LTE networks, load balancing between macro cells and home NodeBs is challenging due to differences in network structures and coverage areas, often resulting in handover failures and increased call drop rates when signal quality is not considered during UE relocation.

Innovation Solution

A method where a macro NodeB actively acquires information about target home NodeBs, including cell type, access attributes, and geographic location, to select the best NodeB for handover based on signal quality when macro cell load exceeds a threshold, using expanded or new S1/X2 interface messages, and performs handovers to home NodeBs in Open or Hybrid modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If load balancing is implemented by moving UEs to home NodeBs without considering signal quality, then network capacity is improved, but handover failure rate increases and call drop rate increases

Engineering Contradiction:
Improvenetwork capacityVSAvoidhandover success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where UEs continuously measure and report signal quality metrics (RSRP, RSRQ) to the source eNB. The source eNB uses this feedback information to evaluate whether the target home NodeB is suitable for handover, thereby preventing handover failures while maintaining load balancing effectiveness

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary actions by having the source eNB proactively acquire target node information (including access mode and CSG identity) before initiating handover. This preliminary information gathering allows the network to pre-evaluate handover suitability and avoid selecting inappropriate target nodes, thus reducing call drop rates

Inventive Principle:
Principle #10Preliminary action

2Area of stationary object

If home NodeBs are deployed freely to expand network capacity, then network coverage is improved, but network structure complexity increases

Engineering Contradiction:
Improvenetwork coverageVSAvoidnetwork structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent manages home NodeB deployment by controlling key parameters such as access mode (open/close/hybrid) and CSG identity assignment. By standardizing these parameters and their configuration procedures, the network can support flexible home NodeB deployment while maintaining manageable structural complexity through parameter-based control

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If macro NodeB actively acquires target home NodeB information, then handover accuracy is improved, but signaling overhead increases

Engineering Contradiction:
Improvehandover accuracyVSAvoidsignaling overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent extracts only the essential information needed for accurate handover decision-making, such as target node ID, access mode, and CSG identity. By selectively acquiring only these critical parameters rather than complete node information, the signaling overhead is minimized while handover accuracy is maintained

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2536213B1Method for balancing load, and apparatuses therefor
Publication Date: 2017.05.10 ZTE CORP
  • EP2536213B1 patent drawingFigure 1~2
  • EP2536213B1 patent drawingFigure 3~4
  • EP2536213B1 patent drawingFigure 5~6

AI summary

The present invention discloses a method for acquiring information of a home NodeB, a method for balancing load, and implementation apparatuses thereof, which are used to solve the problem how to guide a UE to move to an appropriate home NodeB when a macro cell performs load balancing. In the present invention, information of a target NodeB is acquired actively through a macro NodeB, and according to an access type of the target NodeB, subscribers of the macro NodeB are timely balanced to the home NodeB which can provide services, thereby reducing a call drop rate resulted from blind handover. Since measurement information of the UE is fully considered, success rate of balancing handover is enhanced, and the object of performing effective load balancing in a home NodeB environment is achieved.