Mobile Device Event Reporting for RRC Idle Mode Coverage

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Solution Overview

Problem

Conventional Minimization of Drive Tests (MDT) and Radio Link Failure (RLF) reporting techniques are insufficient in detecting coverage problems experienced by mobile devices in Radio Resource Control (RRC) idle mode, as they only collect data when the device is connected and do not account for time spent searching for a suitable cell after a failure.

Innovation Solution

A method where a mobile device continuously stores event records, including measurements and state transitions, while out of network coverage and reports them to the cellular network upon reconnection, allowing for extended MDT and RLF reporting to identify coverage issues and optimize RRC idle mode parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If conventional MDT functionalities collect measurement results only when the mobile terminal is in a 'camped normally' state, then the network can obtain coverage information from connected devices, but coverage problems experienced by devices in idle mode (including those not normally camped) cannot be discovered

Engineering Contradiction:
Improvecoverage informationVSAvoidreporting capability
Core Design Contradiction:
Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by configuring the mobile terminal to store MDT measurement information in advance during idle mode, before actual reporting is needed. The terminal continuously logs measurement data, cell reselection events, and radio link failure information locally, so that when a reporting opportunity arises (device reconnects to network), the pre-collected data can be immediately transmitted. This resolves the contradiction by ensuring coverage information is captured regardless of the device's connection state.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism by using the mobile terminal itself as a data collection and storage intermediary between the idle state devices and the network. The terminal acts as a local database that accumulates coverage measurements and reports them when conditions permit, bridging the gap between devices that cannot report in real-time (idle mode) and the network that needs the information for coverage optimization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If RLF reports only contain measurement information related to serving cell before failure and recovery cell after recovery, then the reporting mechanism remains simple, but information about the time the mobile terminal spends in RRC idle mode trying to find a suitable cell is lost

Engineering Contradiction:
Improveidle mode measurement informationVSAvoidreporting mechanism
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent merges previously separate reporting mechanisms (MDT logging and RLF reporting) into a unified approach. The terminal combines idle mode measurement information, cell reselection data, and radio link failure details into a single comprehensive report that is transmitted together. This integration ensures that all relevant coverage information is captured in one reporting event, resolving the information loss without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies preliminary action by pre-configuring the terminal to log and store detailed measurement information during idle mode and after radio link failures, before the actual reporting occurs. The terminal continuously monitors and records parameters such as reference signal received power, cell identities, and timing information, so that when reporting is triggered, all necessary data is already prepared and stored locally.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If the mobile terminal continuously stores event records while out of network coverage, then comprehensive coverage data can be collected, but the device must maintain storage and processing functions without network connection

Engineering Contradiction:
Improvecoverage problem dataVSAvoiddata storage and reporting mechanism
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the mobile terminal to autonomously perform data collection, storage, and management functions without requiring continuous network connection or external control. The terminal independently logs measurement events, manages its own data buffer, and automatically triggers reporting when it reconnects to the network. This self-sufficient approach allows comprehensive data collection in idle mode while keeping the implementation manageable by leveraging existing terminal capabilities.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2934039B1Technique for event reporting
Publication Date: 2019.03.20 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2934039B1 patent drawingFigure 1~3
  • EP2934039B1 patent drawingFigure 4~5
  • EP2934039B1 patent drawingFigure 6~7

AI summary

A technique for reporting events from a mobile device to a cellular network (100) is provided. The mobile device is wirelessly connectable to the cellular network (100). As to a method aspect of the technique, records of the events are stored while the mobile device is out of network coverage. The stored records are reported to the cellular network (100) when the mobile device is wirelessly connected to the cellular network (100).