# US 11,444,676 B2 · User terminal and radio communication method

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- Number: US 11,444,676 B2
- Document ID: US11444676B2
- Status: Granted
- Kind: B2
- Application number: 16/958,452
- Filed: 2017-12-27
- Published: 2021-02-25
- Granted: 2022-09-13
- Earliest claimed: 2017-12-27
- Assignees: Ntt Docomo, Inc.
- Applicants: Ntt Docomo, Inc.
- Inventors: Kazuki Takeda; Satoshi Nagata; Lihui Wang; Chongning Na; Xiaolin Hou
- Web page: https://patentgrep.com/patent/US11444676B2

## CPC

- H04B 7/06964: {Re-selection of one or more beams after beam failure}
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/088: {using beam selection}
- H04W 16/28: using beam steering
- H04W 28/0278: {using buffer status reports (dynamic wireless traffic scheduling definition H04W72/12)}
- H04W 36/305: {Handover due to radio link failure (control signalling for hand-off failure H04W36/0079)}
- H04W 52/365: {Power headroom reporting}
- H04W 72/1268: of uplink data flows
- H04W 76/19: Connection re-establishment
- H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports}
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04W 74/0838: using contention-free random access [CFRA]
- H04W 76/15: Setup of multiple wireless link connections
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

To perform a beam failure recovery procedure by using an appropriate radio resource, a user terminal includes a transmitting section that transmits a beam failure recovery request, and a control section that controls transmission of the beam failure recovery request by using at least one of an uplink shared channel, an uplink control channel, a sounding reference signal, and a random access channel indicated by a downlink control channel.

## Claims

### Claim 1

A terminal comprising:
a processor that detects a beam failure in a secondary cell; and
a transmitter that transmits a beam failure recovery request by using a scheduling request (SR), applicable for beam failure recovery on the secondary cell, on a physical uplink control channel, based on a configuration of the physical uplink control channel for the beam failure recovery by higher layer signaling, and transmits on a physical uplink shared channel, a Medium Access Control Control Element (MAC CE) including a reference signal ID corresponding to a candidate beam.

### Claim 2 (depends on 1)

The terminal according to claim 1, wherein the transmitter transmits the beam failure recover request in a primary cell or a primary secondary cell.

### Claim 3

A radio communication method for a terminal, comprising:
detecting a beam failure in a secondary cell;
transmitting a beam failure recovery request by using a scheduling request (SR), applicable for beam failure recovery on the secondary cell, on a physical uplink control channel, based on a configuration of the physical uplink control channel for the beam failure recovery by higher layer signaling; and
transmitting on a physical uplink shared channel, a Medium Access Control Control Element (MAC CE) including a reference signal ID corresponding to a candidate beam.

### Claim 4

A system comprising a terminal and a base station, wherein
the terminal comprises:
a processor that detects a beam failure in a secondary cell; and
a transmitter that transmits a beam failure recovery request by using a scheduling request (SR), applicable for beam failure recovery on the secondary cell, on a physical uplink control channel, based on a configuration of the physical uplink control channel for the beam failure recovery by higher layer signaling, and transmits on a physical uplink shared channel, a Medium Access Control Control Element (MAC CE) including a reference signal ID corresponding to a candidate beam, and
the base station comprises:
a receiver that receives the beam failure recovery request and the MAC CE.