Beam Failure Recovery in Multi-Carrier Wireless Systems

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing and recovering from beam failures in multi-carrier communications, particularly at higher frequencies such as those equal to or greater than 6 GHz.

Innovation Solution

A system and method for beam failure recovery and management in a wireless transmit/receive unit (WTRU) configured for multi-carrier communications using beamforming. The WTRU monitors for beam failure on a secondary cell, selects a candidate beam, determines an uplink resource, and transmits a MAC control element indicating beam failure and the selected candidate beam. It then verifies the downlink quasi co-location reference and transmits a random access preamble on the selected candidate beam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If beamforming is implemented at higher frequencies (≥6 GHz) to compensate for increased path loss, then beamforming gain is improved, but system complexity increases due to the need for multiple antenna elements and sophisticated beam management

Engineering Contradiction:

Improvebeamforming gainVSAvoidantenna element quantity and beam management complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent segments the beam management process into distinct phases: beam failure detection, candidate beam identification, and recovery execution. Each phase is handled by specific protocol layers (physical layer for detection, MAC layer for reporting), dividing the complex beam management task into manageable, modular components that reduce overall system complexity while maintaining beamforming gain

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate reference signals (CSI-RS, SSB) as mediators between the transmitted beam and the receiver. These reference signals serve as proxies for beam quality assessment, allowing the system to evaluate beam performance without directly measuring the data channel, thereby simplifying the beam management process at higher frequencies

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the WTRU transmits beam failure indication and candidate beam information via MAC CE on the SpCell, then recovery reliability is improved, but transmission time increases due to the need to switch to the primary cell

Engineering Contradiction:

Improvebeam failure recovery reliabilityVSAvoidrecovery time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring uplink resources on the SpCell for beam failure indication transmission before failure occurs. The network pre-allocates PUCCH resources or PUSCH grants, so when beam failure is detected, the WTRU can immediately use these pre-prepared resources without waiting for resource allocation, thus reducing recovery time while maintaining reliable transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamic resource selection where the WTRU can adaptively choose between different uplink resources (PUCCH, PUSCH, random access) based on current channel conditions and failure severity. This dynamic approach allows the system to balance between reliability and speed, selecting the fastest available path for each specific failure scenario

Inventive Principle:

Principle #15Dynamics

3Reliability

If the WTRU monitors multiple candidate beams for recovery, then recovery success probability is improved, but monitoring complexity and energy consumption increase

Engineering Contradiction:

Improverecovery success probabilityVSAvoidmonitoring energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by having the WTRU monitor only a subset of candidate beams at any given time rather than all possible beams. The WTRU identifies and focuses monitoring efforts on the most promising candidate beams (e.g., those with highest historical signal quality or strongest reference signal measurements), achieving sufficient recovery success probability while significantly reducing monitoring complexity and energy consumption compared to exhaustive monitoring

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20250185099A1Methods and systems for beam recovery and management

Publication Date: 2025.06.05 INTERDIGITAL PATENT HOLDINGS INC

AI summary

A system and methods for beam failure recovery and management for multi-carrier communications with beamforming are disclosed herein. A wireless transmit/receive unit (WTRU) may monitor for and detect a beam failure of a beam associated with a secondary cell (Scell). The WTRU may select an Scell candidate beam. The WTRU may transmit using a selected uplink (UL) resource in a primary cell (SpCell) a medium access control (MAC) control element (CE) including an indication of Scell beam failure and identifying the selected candidate beam. The WTRU may receive an Scell beam failure indication response on the SpCell indicating an SCell index and a downlink (DL) quasi co-location (QCL) reference associated with the Scell. The WTRU may verify that the DL QCL reference matches with the candidate beam. The WTRU may perform random access on the SCell using the selected QCL reference and the selected candidate beam.