Radio Link Failure Timer Segmentation for 5G Beam Recovery

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Solution Overview

Problem

Current radio link failure detection methods in wireless communication networks, such as LTE and 5G, are inefficient, leading to reduced user experience due to delayed detection of radio link failures, which affects the ability of user equipment (UE) to quickly switch to alternative connections or idle modes.

Innovation Solution

The implementation of new timers and indication processing methods, including aperiodic out-of-sync and in-sync indications, allows for more efficient detection of radio link failures by the UE, enabling quicker identification of physical layer problems and initiation of recovery procedures, thereby improving handover processes and user experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional T310 timer is used for radio link failure detection, then the UE can detect physical layer problems, but the detection is delayed and user experience is reduced

Engineering Contradiction:
Improveradio link failure detection accuracyVSAvoiddetection delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the traditional single T310 timer into multiple specialized timers: T310 for traditional out-of-sync indications, T319 for beam failure recovery, and T320 for aperiodic indications. This segmentation allows each timer to be optimized for specific detection scenarios, improving overall detection precision while reducing delays through targeted timer expirations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by introducing a beam failure recovery procedure that activates before declaring radio link failure. When beam failure is detected, the UE starts T319 timer and attempts recovery using candidate beams. This preliminary recovery action prevents unnecessary failure declarations and reduces detection delays by resolving issues before they escalate.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the UE continuously monitors radio link status, then detection accuracy improves, but energy consumption increases

Engineering Contradiction:
Improveradio link monitoring accuracyVSAvoidUE battery consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action through the T320 timer which is triggered by aperiodic out-of-sync indications rather than continuous monitoring. The UE monitors for these specific indications at intervals defined by the timer, maintaining detection accuracy while significantly reducing continuous energy consumption compared to constant monitoring approaches.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies self-service by enabling the UE to autonomously perform beam failure recovery using locally stored candidate beam information. The UE independently evaluates candidate beams and executes recovery procedures without continuous network intervention, reducing monitoring overhead and energy consumption while maintaining high detection accuracy.

Inventive Principle:
Principle #25Self-service

3Reliability

If beam failure recovery procedure is implemented, then radio link reliability improves, but device complexity increases

Engineering Contradiction:
Improveradio link reliabilityVSAvoidtimer management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the timer activation and interaction rules adaptive based on the detection scenario. The system dynamically selects which timers to activate (T310, T319, or T320) depending on whether traditional out-of-sync, beam failure, or aperiodic indications are triggered. This dynamic approach maintains reliability across different scenarios while managing complexity through context-dependent timer selection rather than always-active complex logic.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3659390B1Radio link failure timers and constants based on radio link management and beam failure recovery procedures
Publication Date: 2021.07.14 QUALCOMM INC
  • EP3659390B1 patent drawingFigure 1
  • EP3659390B1 patent drawingFigure 2
  • EP3659390B1 patent drawingFigure 3

AI summary

In an aspect, a scheduled entity obtains a first set of indications associated with a beam failure recovery procedure, starts at least one of a first timer or a second timer based on the obtained first set of indications, and detects a radio link failure when the first timer expires or when the second timer expires. In some aspects, the scheduled entity starts at least one of the first timer or the second timer when N out-of-sync indications are obtained over a network configured time window, the N out-of-sync indications including aperiodic out-of-sync indications from the first set of indications and out-of-sync indications associated with a radio link monitoring procedure. In some aspects, the scheduled entity starts at least the second timer when the first set of indications includes a single aperiodic out-of-sync indication.