# US 11,451,313 B2 · Detection method and user equipment

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- Number: US 11,451,313 B2
- Document ID: US11451313B2
- Status: Granted
- Kind: B2
- Application number: 16/495,734
- Filed: 2018-03-21
- Published: 2020-01-23
- Granted: 2022-09-20
- Earliest claimed: 2017-03-22
- Assignees: Ntt Docomo, Inc.
- Applicants: Ntt Docomo, Inc.
- Inventors: Jing Wang; Liu Liu; Huiling Jiang; Hiroki Harada
- Web page: https://patentgrep.com/patent/US11451313B2

## CPC

- H04B 7/0617: {for beam forming}
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/0408: using two or more beams, i.e. beam diversity
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H04L 5/0057: {Physical resource allocation for CQI}
- H04W 24/08: Testing, {supervising or monitoring} using real traffic
- H04W 76/19: Connection re-establishment
- H04L 5/001: {the frequencies being arranged in component carriers}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Disclosed is a method for detecting radio link failure (RLF) and user equipment (UE). The UE is configured with multiples pairs of beams, each pair of beams comprising a transmitting beam used by a base station (BS) to transmit a signal and a corresponding receiving beam used by the UE to receive the signal. The method includes: in a lower layer, measuring the quality of a reference signal received through a receiving beam in each pair of beams and transmitted by a BS using a transmitting beam corresponding to the receiving beam, to serve as the channel quality for the multiple transmitting beams included in the multiple pairs of beams; determining whether the channel quality for the multiple transmitting beams meets a first condition; if so, transmitting to an upper layer an Out-Of-Sync (OOS) indication information, such that the upper layer determines if, according to the OOS indication information, RLF has occurred. As such, the present invention enables detection of RLF in a multi-beam scenario.

## Claims

### Claim 1

A terminal comprising:
a processor that measures radio quality by using reference signals transmitted by one base station using a plurality of transmitting beams, which include serving beams and candidate beams; and
a transceiver that transmits an indication related to beam failure in an upper layer in case where the radio quality measured by using reference signals transmitted using the serving beams satisfies a condition,
wherein in case where the radio quality measured by using reference signals transmitted using the serving beams satisfies the condition, the processor selects, based on a reception power of the reference signals, a receiving beam corresponding to one of the candidate beams, and
wherein the reference signals comprise both a synchronization signal block and a channel state information reference signal.

### Claim 2 (depends on 1)

The terminal of claim 1, wherein the condition is that the radio quality is lower than a threshold.

### Claim 3

A method comprising:
measuring radio quality by using reference signals transmitted by one base station using a plurality of transmitting beams which include serving beams and candidate beams; and
transmitting an indication related to beam failure in an upper layer in case where the radio quality measured by using reference signals transmitted using the serving beams satisfies a condition,
wherein in case where the radio quality measured by using reference signals transmitted using the serving beams satisfies the condition selecting, based on a reception power of the reference signals, a receiving beam corresponding to one of the candidate beams, and
wherein the reference signals comprise both a synchronization signal block and a channel state information reference signal.

### Claim 4

A system comprising a base station and a terminal, wherein:
the base station comprises:
a processor that controls transmission of reference signals used for measuring radio quality using a plurality of transmitting beams, which include serving beams and candidate beams, and
the terminal comprises:
a processor that measures radio quality by using the reference signals transmitted by the base station; and
a transceiver that transmits an indication related to beam failure in an upper layer in case where the radio quality measured by using reference signals transmitted using the serving beams satisfies a condition,
wherein in case where the radio quality measured by using reference signals transmitted using the serving beams satisfies the condition, the processor of the terminal selects, based on a reception power of the reference signals, a receiving beam corresponding to one of the candidate beams, and
wherein the reference signals comprise both a synchronization signal block and a channel state information reference signal.