Radio Link Monitoring Timer Control for RRC Re-establishment

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Solution Overview

Problem

In the LTE wireless communication system, repeated triggering of the RRC connection re-establishment procedure can occur due to radio link problems detected by the physical layer, leading to connection malfunctions and unexpected issues, as the timer-based monitoring system fails to differentiate between ongoing and expired conditions, resulting in double-initiation of re-establishment procedures.

Innovation Solution

Implementing a method that starts and stops a radio link monitoring timer or counter during an RRC connection re-establishment procedure, ensuring the timer or counter is halted when still running and has not expired, to prevent unnecessary re-initiation of the procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the RRC layer starts a timer to monitor radio link problems, then the system can detect connection issues and initiate re-establishment procedures, but the timer may expire and trigger another re-establishment procedure before the first one completes, causing connection malfunctions

Engineering Contradiction:

Improveconnection stabilityVSAvoidre-establishment procedure timing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by stopping the radio link monitoring timer when an RRC connection re-establishment procedure is triggered. This prevents the timer from expiring during the re-establishment process, thereby avoiding the initiation of another re-establishment procedure before the first one completes. The timer is stopped in advance of potential expiration, eliminating the timing conflict that causes connection malfunctions.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the system triggers RRC connection re-establishment procedure upon detecting lower layer problems, then connection recovery can be initiated, but repeated triggering of the same procedure causes unexpected problems and connection failures

Engineering Contradiction:

Improveconnection recovery capabilityVSAvoidrepeated re-establishment triggering

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback by monitoring the state of the radio link monitoring timer and using this information to control the triggering of RRC connection re-establishment procedures. When the timer is running and has not expired, the system provides feedback to prevent additional re-establishment triggers, thereby avoiding repeated procedure initiation that leads to connection failures.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

By stopping the timer preliminarily when a re-establishment procedure is triggered, the system prevents the condition that would lead to repeated triggering. This preliminary action eliminates the harmful effect of multiple simultaneous re-establishment attempts.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8553569B2Method of connection re-establishment and related communication device

Publication Date: 2013.10.08 INNOVATIVE SONIC LTD

AI summary

A method of connection re-establishment for a user equipment (UE) in a wireless communication system includes starting a radio link monitoring timer or a radio link monitoring counter, and stopping the radio link monitoring timer or the radio link monitoring counter if it is still running when a radio resource control (RRC) connection re-establishment procedure is triggered.