CS Fallback Delay Reduction via Idle Mode Measurement

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Solution Overview

Problem

The existing circuit-switched fallback (CS fallback) process in wireless telecommunications systems experiences delays and reliability issues due to lengthy measurement steps and unnecessary communication processes when transitioning from a network that only provides packet-switched services to one that offers circuit-switched services, particularly when the target cell is in a different location area or requires system information acquisition.

Innovation Solution

The implementation of a more efficient measurement algorithm and reduced communication steps, including the use of idle mode measurement data to minimize delay and improve reliability during CS fallback, allowing user equipment to quickly identify and connect to the most suitable CS network cell, and optimizing the CS fallback process by eliminating unnecessary steps and leveraging pre-measured idle mode data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the existing CS fallback measurement process is used, then the UE can identify suitable CS network cells, but the process experiences lengthy delays due to extensive measurement steps and communication processes

Engineering Contradiction:
Improvereliability of CS fallbackVSAvoiddelay in CS fallback
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the UE perform and store measurement data for CS network cells during idle mode before the actual CS fallback is needed. When CS fallback is triggered, the UE can directly utilize these pre-acquired measurements and identify suitable target cells without performing lengthy measurement procedures, thereby significantly reducing fallback delay while maintaining reliable cell selection

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and eliminates unnecessary communication steps between the UE and the network during the CS fallback process. By using pre-stored measurement data, the UE can autonomously identify suitable CS cells without requiring extensive back-and-forth signaling with the network, thus reducing communication overhead and process delay

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the UE performs extensive system information acquisition for target cells, then the UE can ensure reliable connection, but the process time increases significantly

Engineering Contradiction:
Improveconnection reliabilityVSAvoidsystem information acquisition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the UE acquire and store system information for neighboring CS network cells during idle mode before CS fallback is needed. When fallback is triggered, the UE can directly utilize this pre-acquired system information along with stored measurement data to quickly identify and connect to suitable target cells without performing extensive real-time information acquisition, thereby reducing delay while ensuring reliable connection

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the UE follows the standard CS fallback communication process, then the network can manage the fallback, but unnecessary communication steps increase the process complexity and delay

Engineering Contradiction:
Improvenetwork control of fallbackVSAvoidcommunication process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and removes unnecessary communication steps from the standard CS fallback process. By enabling the UE to autonomously identify suitable CS target cells using pre-stored measurement data and system information, the patent eliminates redundant signaling between the UE and network, thereby reducing communication process complexity and delay while maintaining essential network control for managing the fallback procedure

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2443871B1Method for accessing a service unavailable through a network cell
Publication Date: 2021.12.29 BLACKBERRY LTD
  • EP2443871B1 patent drawingFigure 1
  • EP2443871B1 patent drawingFigure 2
  • EP2443871B1 patent drawingFigure 3

AI summary

A method in user equipment (UE) associated with a first network cell in a wireless telecommunications system includes performing idle mode measurements of one or more network cells other than the first network cell when the UE is operating in an idle mode, receiving a request to access a first service unavailable through the first network cell, communicating with an access device associated with the first network cell based on results of the idle mode measurements, receiving from the access device an identification of a second network cell, and accessing the first service through the second network cell.