Base Station Interference Mitigation via PLMN Detection

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Solution Overview

Problem

Current wireless communication systems face challenges in timing alignment and inter-operator co-existence on unlicensed spectrum, particularly in efficiently managing LTE cell discovery and interference mitigation.

Innovation Solution

A method and apparatus for a base station to receive system information, identify PLMN identities, and select channels for secondary serving cells in an unlicensed band, aligning ON-OFF cycle operations with other transmission points to minimize interference and enable efficient co-existence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If base stations operate on unlicensed spectrum without coordination, then spectrum utilization increases, but inter-operator interference increases

Engineering Contradiction:
Improvespectrum utilizationVSAvoidinter-operator interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent combines timing alignment mechanisms with PLMN identity-based channel selection to coordinate operations across different operators. By merging synchronization signals and systematic information blocks with operator identification, the system enables cooperative spectrum usage while maintaining operator independence, thus increasing overall spectrum utilization without excessive interference.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system implements feedback through systematic information blocks that convey timing and channel allocation information. Base stations receive and process systematic information from other operators, using this feedback to adjust their channel selection and timing, thereby coordinating spectrum usage and reducing inter-operator interference while maintaining high utilization.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If base stations use different channels in unlicensed band, then interference is reduced, but spectrum efficiency decreases

Engineering Contradiction:
ImproveinterferenceVSAvoidspectrum efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent implements dynamic channel selection based on PLMN identity and systematic information. Instead of static channel allocation, base stations dynamically adjust their channel usage according to operator identity and detected systematic information, enabling flexible spectrum sharing that reduces interference while maintaining high efficiency through adaptive resource utilization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (channel selection, timing alignment) based on PLMN identity and received systematic information. By varying these parameters dynamically according to operator characteristics and spectrum conditions, the system achieves both interference reduction and high spectrum efficiency through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If base stations align timing operations, then interference is reduced, but coordination complexity increases

Engineering Contradiction:
ImproveinterferenceVSAvoidcoordination complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent enables base stations to perform self-service timing alignment by autonomously detecting systematic information blocks from other operators and automatically adjusting their operations accordingly. This self-service mechanism reduces the need for complex external coordination while achieving interference reduction through autonomous timing synchronization based on operator identity.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If base stations detect system information from other operators, then channel selection accuracy improves, but information processing load increases

Engineering Contradiction:
Improvechannel selection accuracyVSAvoidinformation processing load
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system extracts only the essential information (PLMN identity and timing parameters) from systematic information blocks rather than processing complete system information. This extraction approach maintains channel selection accuracy by focusing on critical identification data while significantly reducing information processing load and energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3138219B1Method and base station for mitigating inter-operator interference
Publication Date: 2019.09.04 SAMSUNG ELECTRONICS CO LTD
  • EP3138219B1 patent drawingFigure 1a~1b
  • EP3138219B1 patent drawingFigure 2a
  • EP3138219B1 patent drawingFigure 2b

AI summary

An eNodeB operated by a first operator is able to align an ON-OFF cycle operation for interference avoidance. The eNodeB receives, from another eNodeB operated by a second operator a physical broadcast channel (PBCH) and a physical downlink shared channel (PDSCH). A transmission coverage of the eNodeB partially overlaps with a transmission coverage of the other eNodeB. The PBCH carries a master information block (MIB), and the PDSCH carries a single system information block (SIB) identifying available unlicensed channel and including public land mobile network (PLMN) identities for networks operating using the unlicensed channel. The eNodeB uses the MIB and SIB1 to identify that the second eNodeB is operated by the second operator.