Cell Registration Threshold Adjustment for CSFB Signal Weakness

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Solution Overview

Problem

In environments with weak network signals, Mobile Terminated (MT) calls often fail when dual-mode or multi-mode terminals with LTE and UTRAN/GERAN access capabilities fall back to 2G Mobile Communication Technology networks, leading to poor user experience due to insufficient signal strength for successful circuit-switched fallback (CSFB).

Innovation Solution

A cell registration method and device that acquires System Information (SI3) including a signal strength threshold for a first cell upon receiving a CSFB paging message, allowing registration to the cell when the current signal strength is less than the threshold but greater than a preset cell resident signal strength threshold, thereby avoiding registration failure in weak signal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal device uses traditional cell registration method with fixed signal strength threshold, then the registration process is simple, but the MT call fails in weak signal environments

Engineering Contradiction:
ImproveMT call success rateVSAvoidcell registration process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the signal strength threshold adjustable rather than fixed. The terminal device dynamically adapts the threshold based on whether it is in CSFB mode, using a first threshold when CSFB is enabled and a second threshold when it is not. This dynamic adjustment allows successful registration in weak signal environments while maintaining normal operation in strong signal conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of signal strength threshold based on the CSFB mode status. When CSFB is enabled, a more lenient first threshold is used to allow registration in weaker signals, while when CSFB is disabled, a stricter second threshold is used. This parameter change resolves the contradiction by adapting the registration criteria to the operational context.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the terminal device lowers the signal strength threshold to register in weak signal environments, then MT call success improves, but registration may occur with insufficient signal quality

Engineering Contradiction:
ImproveMT call success rateVSAvoidpoor signal quality
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the signal strength threshold parameter based on CSFB mode, using a first threshold that is lower than the second threshold. This allows registration in weaker signal conditions when CSFB is enabled, improving MT call success while the system manages signal quality through the CSFB mechanism.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces CSFB mode as an intermediary mechanism that mediates between registration requirements and signal quality. When the primary cell signal is weak, CSFB enables registration with a adjusted threshold, and the system manages the transition to appropriate network modes to maintain call quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the terminal device requires high signal strength for cell registration, then call quality is maintained, but registration fails in weak signal environments

Engineering Contradiction:
Improvesignal qualityVSAvoidcell registration success
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies dynamics by adjusting the signal strength threshold based on CSFB mode status. When CSFB is enabled, a lower first threshold allows registration in weak signal environments. When CSFB is disabled, a higher second threshold maintains signal quality requirements. This dynamic adaptation resolves the contradiction between registration success and signal quality.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the signal strength threshold parameter according to operational mode. The first threshold is set lower to enable registration in weak signals when CSFB is available, while the second threshold is higher to ensure quality when CSFB is not used. This parameter adaptation allows the system to balance registration success with signal quality maintenance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3565308B1Method and device for registering to a cell
Publication Date: 2021.10.27 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3565308B1 patent drawingFigure 1
  • EP3565308B1 patent drawingFigure 2
  • EP3565308B1 patent drawingFigure 3

AI summary

Disclosed are a cell registration method and device. The method may include: when receiving a paging message of a Circuit Switched FallBack (CSFB), System Information (SI3) of a first cell is acquired, the SI3 including a first signal strength threshold of the first cell which a terminal device resides; the first cell is registered when a current signal strength of the first cell is less than the first signal strength threshold and greater than a preset cell resident signal strength threshold of the terminal device. The present disclosure can solve the problem that the Mobile Terminated call may fail in an environment where the network signal is weak, and improve the user communication experience.