Terminal Cell Selection After Call End to Reduce Location Area Updates

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Solution Overview

Problem

In wireless communication systems, terminals face inconvenience and increased power consumption due to the location area update procedure after ending a call, which can result in missed received calls and excessive battery usage.

Innovation Solution

The method involves storing information about cells on which the terminal has camped, including frequency and signal strength, and performing a cell search to select the cell with the best signal strength matching the previous call's cell, thereby minimizing location area updates and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal performs a location area update procedure after ending a call, then the terminal updates its location information, but the terminal consumes additional battery power

Engineering Contradiction:
Improvelocation information accuracyVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The terminal stores the LAC of the call establishment cell in advance. After the call ends, the terminal performs a quick LAC comparison using the stored value, avoiding the need to execute the full location area update procedure when unnecessary, thereby conserving battery power.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of always performing the complete location area update procedure, the terminal performs a partial check by comparing LAC values. Only when the LAC changes does the terminal proceed with the full update, reducing unnecessary energy consumption from complete update executions.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If the terminal always performs location area update after call ending, then the terminal ensures accurate location registration, but the terminal experiences user inconvenience of missing calls and increased power consumption

Engineering Contradiction:
Improvelocation registration accuracyVSAvoiduser convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The terminal stores the LAC of the cell where the call was originally established before ending the call. After the call ends, the terminal checks whether the current cell's LAC matches the stored LAC. If they match, the terminal skips the location area update procedure, having prepared the stored LAC information in advance for quick comparison and decision-making.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The terminal uses the stored LAC as a reference to provide feedback on whether a location area update is necessary. By comparing the current cell's LAC with the stored LAC, the terminal determines whether to proceed with the update, creating a feedback mechanism that avoids unnecessary procedures and improves user convenience.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3017634B1Method and apparatus for selecting cell of terminal in wireless communication system
Publication Date: 2020.04.22 SAMSUNG ELECTRONICS CO LTD
  • EP3017634B1 patent drawingFigure 1~2
  • EP3017634B1 patent drawingFigure 3
  • EP3017634B1 patent drawingFigure 4a~5a

AI summary

A method and an apparatus for selecting a cell of a terminal in a wireless communication system are provided. The method includes detecting, by the terminal, an end of a call, performing, when an end of the call is detected, a cell search based on a cell used during the call, the cell search being performed among at least one cell having been used before the call by the terminal and a cell used just before forming the call, and determining a cell to which the cell selection is performed, based on a result of the cell search and the cell used just before forming the call.