Small Cell Base Station Control Plane Extraction for HetNet Interference

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Solution Overview

Problem

Heterogeneous Networks (HetNets) face challenges in mobility management due to increased handover failures and ping-pongs caused by the large number of small cells overlaid on traditional macro cell networks, leading to network performance issues and subscriber dissatisfaction.

Innovation Solution

A small cell base station is deployed within an overlying cell, determining the presence of the overlying cell and resources allocated for control plane data transmission, and preventing the transmission of user plane data within those resources to minimize interference and handovers, while maintaining capacity by transmitting channel state information-reference signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If small cells are deployed within macro cells to increase network capacity, then network capacity is improved, but handover failures and ping-pongs increase

Engineering Contradiction:

Improvenetwork capacityVSAvoidhandover success rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent extracts the control plane functionality from the small cell base station, leaving only user plane data transmission. By removing the control plane (which handles handovers and mobility management), the small cell cannot initiate handovers that cause failures or ping-pongs, while still providing capacity through user data transmission.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the base station functionality into two independent parts: control plane (handled by macro cell) and user plane (handled by small cell). This segmentation allows the small cell to contribute to network capacity without participating in handover decisions, thereby resolving the contradiction between capacity improvement and handover reliability.

Inventive Principle:

Principle #1Segmentation

2Area of stationary object

If small cells are deployed to provide local coverage, then coverage capacity is improved, but interference with control plane transmissions increases

Engineering Contradiction:

Improvecoverage areaVSAvoidinterference with control plane

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent removes control plane transmission functionality from small cells, eliminating the source of interference with macro cell control plane transmissions. Small cells transmit only user plane data, which does not interfere with control plane signals used for mobility management.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different transmission qualities to different parts of the network: macro cells handle control plane transmissions with high reliability, while small cells handle user plane data transmission. This local differentiation ensures that small cell transmissions do not degrade control plane signal quality.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If small cells are made visible to user equipment, then user equipment can connect to small cells, but handover complexity increases

Engineering Contradiction:

Improveconnection flexibilityVSAvoidhandover management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the cell identification and handover trigger functionality from small cells by removing control plane transmissions. User equipment cannot detect small cells as handover targets, eliminating the complexity of managing handovers to and from small cells, while user plane connectivity is maintained through alternative mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP2824958B1Wireless telecommunications network nodes and methods

Publication Date: 2017.01.11 ALCATEL LUCENT SA

AI summary

Wireless telecommunications network nodes, methods and computer program products are disclosed. A small cell base station for deployment within an overlying cell supported by an overlying cell base station of a wireless telecommunications network and operable to support communication with user equipment, the small cell base station comprises: determining logic operable to determine a presence of the overlying cell and to determine resources allocated for transmission of control plane data by the overlying base station; transmission logic operable to support transmission only of user plane data with the user equipment; and preventing logic operable to prevent transmission of any user plane data within the resources allocated for transmission of control plane data by the overlying cell base station. By transmitting only user plane or selected data, the small cell base station can prevent itself from transmitting that data which identifies itself as a cell to user equipment and thereby prevent user equipment from initiating handover to that small cell. Also, by preventing transmission of the user plane or selected data within those resources which are allocated for transmission of control plane data by the overlying cell base station, any interference caused by transmissions by the small cell are minimised on those control plane transmissions from the overlying cell base station in order to maintain adequate reception of vital control plane transmissions. This helps to ensure that user plane or selected data transmissions can be made from the small cell base station in order to boost capacity where required, without needing to perform handover to those small cells and without causing interference to the control plane transmissions being made by the overlying cell base station.