HeNB Pilot Power Adjustment for Constant Reselection Range

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Solution Overview

Problem

In 3GPP LTE systems, maintaining a constant reselection range for home evolved NodeBs (HeNBs) is challenging due to varying transmission ranges caused by different Q Factors used by eNodeBs and HeNBs, leading to inconsistent coverage and potential coverage gaps.

Innovation Solution

The method involves using an offset factor and HeNB pilot power to establish a reselection area around HeNBs, with adaptive pilot power transmission to maintain a constant reselection range by estimating path loss between HeNBs and eNodeBs, ensuring uniform coverage across the cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a constant Q Factor is used throughout a cell, then the reselection algorithm can be simplified, but different transmission ranges for each HeNB result in inconsistent coverage and potential coverage gaps

Engineering Contradiction:
Improvereselection algorithm complexityVSAvoidcoverage consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by allowing each HeNB to have its own Q Factor value tailored to its specific location and propagation conditions within the cell, rather than using a uniform Q Factor across the entire cell. This enables each HeNB to optimize its coverage area independently, ensuring consistent coverage without gaps while maintaining manageable algorithm complexity through localized parameter adjustment.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If Qoffset is used to control UE mobility, then cell reselection can be biased toward desired eNodeBs, but the reselection range becomes variable and coverage uniformity is compromised

Engineering Contradiction:
ImproveUE mobility controlVSAvoidcoverage uniformity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs parameter changes by dynamically adjusting the Q Factor parameter for each HeNB based on its separation distance from the eNodeB and propagation conditions. This allows the system to maintain uniform coverage areas while still providing biased mobility control toward desired HeNBs, as each HeNB's Q Factor is optimized to create consistent reselection ranges despite varying locations and signal conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2345290B1Systems and methods for configuration of offset factors and maintenance of constant reselection range in a wireless communication environment
Publication Date: 2019.12.25 NOKIA TECHNOLOGIES OY
  • EP2345290B1 patent drawingFigure 1
  • EP2345290B1 patent drawingFigure 2
  • EP2345290B1 patent drawingFigure 3

AI summary

A method for self-configuration of offset factors between two base stations in a wireless communications system is described. A first offset factor is sent to a first user equipment (UE) by a first base station. An offset factor is an indication of the reselection area around a home evolved nodeB (HeNB). A second offset factor is received from a second UE. The first offset factor is modified using the second offset factor. The modified first offset factor is sent to the first UE.