Small Cell PCI Confusion Detection and Resolution

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Solution Overview

Problem

In LTE wireless communication systems, PCI confusion occurs when small cells have duplicate PCI values, leading to handover failures due to insufficient neighbor information acquisition status between small cell base stations, resulting in decreased handover success rates.

Innovation Solution

A communication apparatus and method that includes a communication status acquisition unit and a control unit in small cell base stations to detect and eliminate PCI confusion by counting the number of handover failures and autonomously re-selecting or requesting a new PCI value when the number of failures meets a predetermined threshold, regardless of neighbor information acquisition status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If small cell base stations autonomously re-select PCI values to eliminate PCI confusion, then handover success rate is improved, but device complexity increases due to autonomous decision-making requirements

Engineering Contradiction:
Improvehandover success rateVSAvoidbase station complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The small cell base station autonomously detects PCI confusion by monitoring handover failure rates and automatically re-selects PCI values without external intervention. The control unit counts handover failures, compares them against thresholds, and triggers PCI re-selection when confusion is detected, enabling the system to self-diagnose and self-correct the duplication issue

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements a feedback mechanism where the small cell base station monitors handover failure rates as an indicator of PCI confusion. When the failure rate exceeds a predetermined threshold, this feedback triggers the control unit to re-select a different PCI value, creating a closed-loop control system that continuously optimizes handover performance

Inventive Principle:
Principle #23Feedback

2Measurement precision

If small cell base stations acquire neighbor information from macro cell base stations, then PCI confusion detection is improved, but loss of information occurs when neighbor information is insufficient or unavailable

Engineering Contradiction:
ImprovePCI confusion detection accuracyVSAvoidneighbor information insufficiency
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The small cell base station proactively monitors handover failure rates and builds a database of handover performance data before PCI confusion becomes severe. The control unit continuously counts handover failures and maintains readiness to re-select PCI values, preparing the system in advance to handle information gaps about neighboring cells

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system does not rely solely on neighbor information from macro cell base stations. Instead, the small cell base station independently detects PCI confusion through its own handover failure rate monitoring and autonomously makes PCI re-selection decisions, eliminating dependency on potentially incomplete external information

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the system monitors handover failures to detect PCI confusion, then detection precision is improved, but loss of time occurs due to the delay in detecting duplication

Engineering Contradiction:
ImprovePCI confusion detection accuracyVSAvoiddetection delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The control unit implements continuous real-time monitoring of handover failure rates, immediately comparing each new failure count against the predetermined threshold. When confusion is detected through this feedback mechanism, the system triggers immediate PCI re-selection, minimizing the time PCI confusion persists and its impact on handover performance

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system sets predetermined thresholds for handover failure rates that trigger PCI re-selection before the confusion becomes severe. By establishing these thresholds in advance and continuously monitoring against them, the system takes preliminary protective action to prevent extensive handover failures, reducing both detection delay and overall impact

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3200506B1Communication apparatus, wireless communication system and communication method to eliminate cell identifier duplication
Publication Date: 2022.01.12 NEC CORP
  • EP3200506B1 patent drawingFigure 1~2
  • EP3200506B1 patent drawingFigure 3
  • EP3200506B1 patent drawingFigure 4

AI summary

A communication apparatus according to the present invention is applied to a communication apparatus in a wireless communication system including a terminal, a first base station forming a first cell, and a second base station forming a second cell adjacent to the first cell. The communication apparatus includes: a communication status acquisition unit that acquires a communication status in the second base station; and a control unit that eliminates cell identifier duplication between a cell identifier of the second cell and a cell identifier of another cell based on the number of times that the second base station has received, from the terminal, a first message requesting for re-establishment of an RRC connection.