Idle Mode RAT Re-selection via Out-of-Service Search

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Solution Overview

Problem

Mobile devices in wireless communication networks often become stuck on less preferred radio access technologies (RATs) due to the lack of cell reselection parameters for higher-priority RATs within the same public land mobile network (PLMN), preventing seamless transitions to more advanced or cost-effective networks.

Innovation Solution

The mobile device autonomously initiates an out-of-service search procedure for multiple RATs within the same PLMN while in idle mode, determining the priority of detected RATs and camping onto a higher-priority network when available, even if the initial RAT does not broadcast necessary reselection parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the first RAT does not broadcast cell reselection parameters, then the network configuration is simplified, but the UE cannot autonomously transition to higher-priority RATs within the same PLMN

Engineering Contradiction:

Improvenetwork configuration complexityVSAvoidRAT transition capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The UE performs preliminary actions by initiating an out-of-service search procedure to detect and evaluate higher-priority RATs before actually transitioning. This allows the UE to proactively identify available networks and prepare for transition, resolving the contradiction by enabling autonomous decision-making without requiring preliminary broadcast of reselection parameters by the first RAT

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The UE serves itself by autonomously determining RAT priorities and initiating transitions without relying on network-provided reselection parameters. The UE independently evaluates detected RATs, determines their priorities relative to the first RAT, and autonomously camps on higher-priority RATs, thereby achieving adaptability without increasing network configuration complexity

Inventive Principle:

Principle #25Self-service

2Productivity

If the UE continuously searches for higher-priority RATs, then network utilization improves, but power consumption and processing time increase

Engineering Contradiction:

Improvenetwork utilization efficiencyVSAvoidUE power consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The UE implements periodic action by conducting out-of-service searches at intervals rather than continuously. The UE enters idle mode periodically to search for higher-priority RATs and returns to the first RAT when no better options are found or after a timeout period, thereby improving network utilization while controlling power consumption through rhythmic rather than continuous operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The UE applies partial action by performing limited searches for higher-priority RATs only when specific conditions are met (e.g., during idle mode transitions). Rather than continuously monitoring all possible RATs, the UE conducts targeted searches based on trigger events, achieving sufficient network utilization improvement without the excessive energy cost of constant monitoring

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If the UE autonomously determines RAT priority without network parameters, then transition flexibility increases, but the risk of incorrect camp decisions increases

Engineering Contradiction:

ImproveRAT selection flexibilityVSAvoidcamping decision accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The UE implements feedback mechanisms by monitoring the performance and availability of detected RATs during the out-of-service search. The UE evaluates signal quality, network responsiveness, and service availability of potential target RATs before making camping decisions, using this feedback to validate autonomous priority determinations and reduce the risk of incorrect camp decisions while maintaining transition flexibility

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9026112B2Transitioning of mobile devices within a wireless communication network between multiple radio access technologies

Publication Date: 2015.05.05 QUALCOMM INC

AI summary

Network re-selection by an idle mobile device between multiple radio access technologies (RATs) is provided for communication networks without a network-based solution. When a user equipment (UE) enters idle mode while camped to a first RAT network, it initiates an out of service search procedure that causes the UE to search for other RATs within a same public land mobile network (PLMN). If another RAT network is detected, the UE determines whether the priority of the detected RAT is higher than the priority of the first RAT. When the detected RAT has a higher priority than the first RAT, the UE re-selects and camps to that detected RAT network. If the detected RAT does not have a higher priority or no other RAT is detected within the PLMN, the UE re-camps to the first RAT network.