Beam Link Failure Detection in Multi-Beam Radio Systems

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Solution Overview

Problem

Current radio link monitoring (RLM) techniques in LTE and 5G networks face challenges in effectively managing multibeam systems, where multiple beams are used for communication, leading to complexities in detecting link failures and recovering from out-of-sync conditions.

Innovation Solution

Implementing a multibeam RLM framework that tracks each beam separately at the L2 layer, using beam-specific counters and timers to manage beam recovery, and allowing the RRC to declare cell-level RLF based on L2 indications, enabling efficient detection and recovery of link failures across multiple beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If beam-based monitoring is implemented in multibeam systems, then link failure detection precision is improved, but system complexity increases due to multiple beams requiring separate tracking

Engineering Contradiction:
Improvelink failure detection precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the monitoring task into beam-specific segments by introducing beam-specific counters (e.g., Counter 1 for Beam 1, Counter 2 for Beam 2) and beam-specific timers. Each beam is monitored independently with its own failure detection mechanism, allowing precise identification of which specific beam has failed while managing complexity through modular, organized tracking of multiple beams rather than treating them as a single aggregate.

Inventive Principle:
Principle #1Segmentation

2Reliability

If separate beam-specific counters are used for each beam, then beam recovery management is improved, but device complexity increases due to multiple counters and timers

Engineering Contradiction:
Improvebeam recovery managementVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements separate beam-specific counters and timers for each beam to track link quality and recovery status independently. This segmentation allows the system to manage beam recovery on a per-beam basis, improving reliability by identifying and recovering from failures in specific beams without affecting others, while organizing the complexity through structured, modular counter and timer management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-configures beam-specific counters and timers before beam failures occur. These counters are initialized and ready to immediately start counting out-of-sync indications when a beam failure occurs, rather than being created dynamically. This preliminary setup reduces the computational burden during failure events and simplifies the real-time response mechanism.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If beam link failure is determined based on beam-specific out-of-sync indications, then detection accuracy is improved, but processing time increases due to evaluating multiple beams

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the detection process by maintaining separate counters for each beam that independently count out-of-sync indications. This allows the system to quickly determine beam link failure by checking individual beam counters rather than processing all beams simultaneously, improving detection accuracy for specific failed beams while reducing overall processing time through parallel, independent counter management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each beam-specific counter autonomously counts its own out-of-sync indications and triggers beam link failure determination independently when thresholds are met. This self-service mechanism eliminates the need for centralized processing of all beam data, reducing processing time while maintaining accurate detection of beam-specific failures through distributed, autonomous counter operation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3603319B1Beam-based radio link monitoring
Publication Date: 2024.10.16 NOKIA TECHNOLOGIES OY
  • EP3603319B1 patent drawingFigure 1~2
  • EP3603319B1 patent drawingFigure 1A
  • EP3603319B1 patent drawingFigure 3~4B

AI summary

A method including monitoring, by a user equipment (UE) operating in a multi-beam based communication session, signal qualities for a plurality of beams in the multi-beam based communication session (300); determining a beam link failure (BLF) occurring for at least one of the beams in the multi-beam based communication session (302); determining a type of the beam in which the beam link failure (BLF) is occurring (304); and updating a radio link failure (RLF) related condition in dependence on the type of the beam in which the beam link failure (BLF) is occurring (306).