Beam Failure Recovery Using PUCCH Resources

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Solution Overview

Problem

The current beam failure recovery process in NR technologies is hindered by long PRACH resource periods and time delays in transmitting Beam Failure Recovery Requests (BFRQs) due to the use of Physical Random-Access Channel (PRACH) resources.

Innovation Solution

The method involves using a Physical Uplink Control Channel (PUCCH) resource, either pre-allocated by the base station or in a preset format, to send BFRQs after identifying candidate beams, allowing for faster transmission and reducing time delays in informing the base station of beam failures and candidate beam information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If PRACH resource is used for BFRQ transmission, then the transmission can be performed, but the period and time delay for transmitting BFRQ are long

Engineering Contradiction:

Improvetime delay for transmitting BFRQVSAvoidbeam failure recovery speed

Core Design Contradiction:

Loss of timeVSProductivity

Solution Approach 1:

The patent changes the channel type parameter from PRACH to PUCCH for BFRQ transmission. PUCCH has shorter period and lower latency characteristics compared to PRACH, which directly reduces the time delay for BFRQ transmission and accelerates beam failure recovery speed.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent pre-configures PUCCH resources for BFRQ transmission before beam failure occurs. The base station allocates dedicated PUCCH resources to UEs in advance, so that when beam failure detection happens, the UE can immediately use the pre-configured PUCCH resource to send BFRQ without waiting for PRACH opportunity, thereby reducing transmission delay.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If PUCCH resource is used for BFRQ transmission, then the time delay is reduced, but the resource allocation complexity increases

Engineering Contradiction:

Improvetime delay for transmitting BFRQVSAvoidresource allocation complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The base station performs preliminary allocation of PUCCH resources to UEs before beam failure occurs. Through RRC signaling or MAC CE, the base station configures dedicated PUCCH resources for each UE, establishing a mapping relationship between UE and PUCCH resource in advance. This preliminary action simplifies the real-time response process when beam failure occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent enables UEs to autonomously select and use their pre-configured PUCCH resources for BFRQ transmission without requiring real-time scheduling grants from the base station. The UE self-determines which PUCCH resource to use based on its configured mapping relationship, reducing control signaling overhead and base station processing complexity.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11856422B2Beam failure recovery request sending and response methods and devices, and storage medium

Publication Date: 2023.12.26 BEIJING XIAOMI MOBILE SOFTWARE CO LTD

AI summary

A beam failure recovery request sending method includes: after a beam failure event occurs in a terminal, searching for a candidate beam; and after at least one candidate beam is found, using a physical uplink control channel (PUCCH) resource to send a beam failure recovery request (BFRQ) to a base station, the PUCCH resource comprising a PUCCH resource pre-allocated to the terminal by the base station or a PUCCH resource in a preset format. The present disclosure achieves the purpose of transmitting a BFRQ using a PUCCH resource, making the time delay of transmitting a BFRQ small.