CS Fallback Cell Selection Using Idle Mode Measurements

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Solution Overview

Problem

The existing circuit-switched fallback (CS fallback) process in wireless telecommunications systems experiences significant delays and reliability issues due to lengthy measurement steps and unnecessary communication processes when transitioning from a network that does not provide circuit-switched domain services to one that does, particularly when the user equipment (UE) is initially camped on an E-UTRAN cell.

Innovation Solution

A system and method are introduced to optimize the CS fallback process by implementing a more efficient measurement algorithm and minimizing communications, allowing the UE to detect and select the most appropriate CS network cell for fallback, potentially using idle mode measurement data to reduce connected mode measurement duration and eliminate unnecessary steps, thereby reducing delay and improving reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE performs lengthy measurement steps and communication processes during CS fallback, then the UE can reliably select an appropriate CS network cell, but the delay increases significantly

Engineering Contradiction:

Improvereliability of CS fallbackVSAvoiddelay in CS fallback

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The UE performs measurements on CS network cells during idle mode before CS fallback is triggered. These preliminary measurements include detecting cell identities and evaluating signal quality. When CS fallback is subsequently triggered, the UE can immediately utilize these pre-collected measurement results to identify suitable target cells, eliminating the need for lengthy connected-mode measurements and significantly reducing fallback delay while maintaining reliable cell selection

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism where the UE stores measurement data from idle mode as a bridge between idle mode operation and connected mode fallback. This stored measurement information acts as an intermediary resource that enables rapid cell selection during CS fallback without requiring real-time measurements, thus resolving the contradiction between reliability and delay

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of time

If the UE uses idle mode measurement data for CS fallback, then the measurement duration in connected mode is reduced, but the UE must maintain additional measurement capabilities in idle mode

Engineering Contradiction:

Improveconnected mode measurement durationVSAvoidmeasurement capability requirements

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The UE implements universal measurement capabilities that function in both idle mode and connected mode. The same measurement mechanisms and processing logic are used regardless of UE state, allowing measurement data to be effectively utilized in either context. This multi-functionality approach enables the UE to perform measurements during idle mode without requiring separate dedicated measurement systems, thereby reducing connected mode measurement duration while avoiding significant increases in device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12075291B2Method for accessing a service unavailable through a network cell

Publication Date: 2024.08.27 MALIKIE INNOVATIONS LTD

AI summary

A method performed by user equipment (UE) includes receiving a request to access a service unavailable through a first network cell associated with the UE and informing a second network cell that the UE is requesting to obtain the service unavailable through the first network cell. The request may be received from a user of the UE or may be a paging message.