UE Network Scanning for VoLTE Fallback

Solution Overview

Problem

The existing LTE network falls back to legacy 3G networks for voice communications upon detecting service-disrupting events, leading to prolonged scanning times for available LTE bands, battery drain, and potential missed pages, as well as incurring roaming charges when acquiring roaming LTE bands.

Innovation Solution

The user equipment (UE) detects service-disrupting events, deregisters from VoLTE, and scans only the LTE bands within the Home PLMN, allowing immediate connection to circuit-switched communications via the Home Legacy RAN, thereby reducing scanning time and conserving battery power while avoiding roaming charges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UE scans all available LTE bands including roaming bands, then the UE can discover more network options, but the scanning time increases and battery power is drained

Engineering Contradiction:

Improvenetwork option discoveryVSAvoidscanning time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the network scanning process into two distinct phases: first scanning only Home PLMN LTE bands to establish quick connectivity, and separately scanning roaming LTE bands only if needed. This segmentation allows the UE to prioritize time-critical operations (Home PLMN scanning) while maintaining the option to discover additional networks (roaming bands) without the full scanning overhead.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts the roaming band scanning from the mandatory initial scanning process. Instead of including all bands in the primary scan, the UE performs only Home PLMN band scanning first, then separately handles roaming band discovery only when service disruption occurs and Home PLMN bands are unavailable. This extraction reduces the time and energy burden of the primary scanning operation.

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If the UE scans all available LTE bands including roaming bands, then the UE can discover more network options, but battery power is drained

Engineering Contradiction:

Improvenetwork option discoveryVSAvoidbattery power

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the network scanning process into two distinct phases: first scanning only Home PLMN LTE bands to establish quick connectivity, and separately scanning roaming LTE bands only if needed. This segmentation allows the UE to prioritize time-critical operations (Home PLMN scanning) while maintaining the option to discover additional networks (roaming bands) without the full scanning overhead.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by performing only the necessary subset of band scanning (Home PLMN bands) rather than completing the full scanning sequence (all bands including roaming). The UE performs partial scanning sufficient for immediate connectivity needs, avoiding the excessive energy consumption of complete band scanning unless service disruption necessitates further exploration.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If the UE performs full band scanning, then all LTE bands are discovered, but pages may be missed during the scanning process

Engineering Contradiction:

Improveband discovery completenessVSAvoidpage reception

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent segments the network scanning process into two distinct phases: first scanning only Home PLMN LTE bands to establish quick connectivity, and separately scanning roaming LTE bands only if needed. This segmentation allows the UE to prioritize time-critical operations (Home PLMN scanning) while maintaining the option to discover additional networks (roaming bands) without the full scanning overhead.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies the skipping principle by rapidly scanning only the essential Home PLMN bands and immediately establishing connectivity, rather than methodically scanning all bands in sequence. This rushed approach through the critical scanning phase minimizes the window during which pages could be missed, prioritizing quick reconnection over exhaustive band discovery.

Inventive Principle:

Principle #21Skipping (Rushing through)

Data Source

PatentUS9655008B2Systems and methods for improved network scanning for quality of service applications

Publication Date: 2017.05.16 APPLE INC

AI summary

A user equipment (“UE”) that performs methods to connect to multiple radio access networks (RAN) including a home network RANs and roaming RANs to perform communications. An exemplary method performed by a UE initially connected to a Long Term Evolution radio access network (LTE-RAN) of a home network and registered with a voice over LTE (VoLTE) service of the home network to perform voice communications via the LTE-RAN, includes detecting a service disrupting event preventing VoLTE communication with the LTE-RAN, deregistering from the VoLTE service of the home network, scanning for available bands in the LTE-RAN of the home network and while scanning for the available bands in the LTE-RAN of the home network, connecting to a further radio access network (RAN) of the home network that allows circuit-switched communications with the home network, wherein the UE performs voice communications as circuit-switched communications via the further RAN.