# US 12,225,392 B2 · Terminal and communication method for beam failure recovery

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- Number: US 12,225,392 B2
- Document ID: US12225392B2
- Status: Granted
- Kind: B2
- Application number: 17/753,342
- Filed: 2019-09-13
- Published: 2022-09-15
- Granted: 2025-02-11
- Earliest claimed: 2019-09-13
- Assignees: Ntt Docomo, Inc.
- Applicants: Ntt Docomo, Inc.
- Inventors: Hideaki Takahashi; Yuki Matsumura
- Web page: https://patentgrep.com/patent/US12225392B2

## CPC

- H04W 24/04: Arrangements for maintaining operational condition
- H04B 7/00: Radio transmission systems, i.e. using radiation field (H04B10/00, H04B15/00 take precedence)
- H04B 7/06964: {Re-selection of one or more beams after beam failure}
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04W 74/0838: using contention-free random access [CFRA]
- H04W 76/19: Connection re-establishment
- Y02D 30/70: in wireless communication networks
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

A terminal includes a transmitter that transmits a random access preamble; a receiver that receives a random access response; and a controller that uses a spatial filter applied to the transmission of the random access preamble for a transmission of an uplink control signal, in a time interval after the receiver receives the random access response until the receiver receives configuration information of another spatial filter.

## Claims

### Claim 1

A terminal comprising:
a transmitter that transmits a random access preamble, wherein a spatial filter is applied to the transmission of the random access preamble;
a receiver that receives a random access response; and
a controller that is configured to perform a random access procedure for executing beam failure recovery,
wherein before a beam failure recovery time expires, the controller is configured to perform a contention-free random access procedure,
wherein, when the beam failure recovery time expires, the controller is configured to perform a contention-based random access procedure, the random access preamble being applied to the contention-based random access procedure, and
wherein the controller is configured to use the spatial filter applied to the transmission of the random access preamble for a transmission of an uplink control channel (PUCCH), in a time interval after 28 symbols from a last symbol of a first physical downlink control channel (PDCCH) for the random access response and until the receiver receives an activation command for PUCCH-SpatialRelationInfo or until the PUCCH-SpatialRelationInfo is configured.

### Claim 2 (depends on 1)

The terminal according to claim 1, wherein, after the receiver receives the random access response, the controller sets an antenna port quasi-collocation parameter associated with an index for physical downlink control channel (PDCCH) monitoring in a control resource set (CORESET) with an index 0, as an antenna port quasi-collocation parameter.

### Claim 3 (depends on 1)

The terminal of claim 1, wherein, with respect to monitoring of the PDCCH and receipt of a corresponding Physical Downlink Shared Channel (PDSCH), the controller assumes a DeModulation Reference Signal (DM-RS) antenna port quasi-collocation parameter that is a same as a DM-RS antenna port quasi-collocation parameter associated with a Synchronization Signal/Physical Broadcast Channel (SS/PBCH) block selected to transmit the random access preamble.

### Claim 4

A communication method executed by a terminal, the method comprising:
transmitting a random access preamble, wherein a spatial filter is applied to the transmission of the random access preamble;
receiving a random access response; and
performing a random access procedure for executing beam failure recovery,
wherein before a beam failure recovery time expires, the performing performs a contention-free random access procedure,
wherein, when the beam failure recovery time expires, the performing performs a contention-based random access procedure, the random access preamble being applied to the contention-based random access procedure, and
wherein the performing uses the spatial filter applied to the transmission of the random access preamble for a transmission of an uplink control channel (PUCCH), in a time interval after 28 symbols from a last symbol of a first physical downlink control channel (PDCCH) for the random access response and until receiving an activation command for PUCCH-SpatialRelationInfo or until the PUCCH-SpatialRelationInfo is configured.

### Claim 5

A base station comprising:
a receiver that receives a random access preamble from a terminal, wherein a spatial filter is applied to the transmission of the random access preamble;
a transmitter that transmits a random access response; and
a controller that controls an uplink control channel (PUCCH) reception for which the spatial filter applied to the reception of the random access preamble is used, in a time interval after 28 symbols from a last symbol of a first physical downlink control channel (PDCCH) for the random access response and until the transmitter transmits an activation command for PUCCH-SpatialRelationInfo or until the PUCCH-SpatialRelationInfo is configured in the terminal,
wherein the terminal is configured to perform a random access procedure for executing beam failure recovery, the random access procedure being a contention-free random access procedure before a beam failure recovery time expires, and
wherein the random access preamble is applied to a contention-based random access procedure for performing the beam failure recovery after the beam failure recovery time expires.