# US 11,122,642 B2 · Beam failure recovery procedure

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- Number: US 11,122,642 B2
- Document ID: US11122642B2
- Status: Granted
- Kind: B2
- Application number: 16/744,632
- Filed: 2020-01-16
- Published: 2020-05-14
- Granted: 2021-09-14
- Earliest claimed: 2018-01-04
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Hua Zhou; Esmael Dinan; Alireza Babaei; Hyoungsuk Jeon; Kyungmin Park
- Web page: https://patentgrep.com/patent/US11122642B2

## CPC

- H04W 76/19: Connection re-establishment
- H04B 7/0617: {for beam forming}
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/06964: {Re-selection of one or more beams after beam failure}
- H04B 7/088: {using beam selection}
- H04B 17/327: Received signal code power [RSCP]
- H04L 1/0003: {by switching between different modulation schemes}
- H04L 1/0009: {by adapting the channel coding (H04L1/1812 takes precedence)}
- H04L 1/0026: {Transmission of channel quality indication}
- H04L 1/0027: {Scheduling of signalling, e.g. occurrence thereof}
- H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)}
- H04L 1/1819: {with retransmission of additional or different redundancy}
- H04L 27/2692: {with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver}
- H04L 69/22: Parsing or analysis of headers
- H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports}
- H04W 52/146: {Uplink power control}
- H04W 52/221: {using past power control commands}
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04W 76/11: Allocation or use of connection identifiers
- H04B 1/3838: {Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use}
- H04L 1/1822: involving configuration of automatic repeat request [ARQ] with parallel processes
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04W 52/04: Transmission power control [TPC]
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04W 74/0838: using contention-free random access [CFRA]
- H04W 80/02: Data link layer protocols
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A wireless device transmits one or more preambles in response to initiating a beam failure recovery. The wireless device determines a failure of the beam failure recovery based on a number of transmissions of the one or more preambles exceeding a first number. The wireless device determines a radio link failure in response to the failure of the beam failure recovery. The wireless device starts, based on the radio link failure, a radio resource control (RRC) connection re-establishment procedure with a radio link failure report indicating the failure of the beam failure recovery is a cause of the radio link failure.

## Claims

### Claim 1

A method of a wireless device comprising:
receiving one or more RRC messages comprising configuration parameters for a beam failure recovery, wherein the configuration parameters comprises a plurality of reference signals for a beam failure detection, a second number of beam failure instances, a timer value for a response window, and a first number for preamble transmissions;
detecting one or more beam failure instances based on the plurality of the reference signals for the beam failure detection;
determining a beam failure based on a number of detection of the one or more beam failure instances reaching the second number;
initiating a random access procedure for the beam failure recovery;
transmitting one or more preambles in response to initiating the random access procedure for the beam failure recovery;
determining a failure of the beam failure recovery based on a number of transmissions of the one or more preambles exceeding the first number;
determining a radio link failure in response to the failure of the beam failure recovery;
storing a cause of the radio link failure as the failure of the beam failure recovery; and
starting, based on the determination of the radio link failure, a radio resource control (RRC) connection re-establishment procedure.

### Claim 2 (depends on 1)

The method of claim 1, further comprising transmitting, based on the RRC connection re-establishment procedure, one or more RRC messages comprising a radio link failure report including the cause of the radio link failure.

### Claim 3 (depends on 2)

The method of claim 2, further comprising indicating first information to an RRC layer of the wireless device in response to the number of transmissions of the one or more preambles being greater the first number, wherein the first information comprises an indication of the failure of the beam failure recovery.

### Claim 4 (depends on 3)

The method of claim 3, wherein the radio link failure report comprises one or more parameters indicating the failure of the beam failure recovery is the cause of the radio link failure.

### Claim 5 (depends on 1)

The method of claim 1, further comprising monitoring a downlink control channel in a control resource set for reception of a response to the transmitting the one or more preambles.

### Claim 6 (depends on 1)

The method of claim 1, wherein initiating the random access procedure for the beam failure recovery comprises setting a preamble transmission counter to an initial value.

### Claim 7 (depends on 6)

The method of claim 6, wherein determining the failure of the beam failure recovery based on the number of the transmissions of the one or more preambles exceeding the first number comprising:
starting the response window based on the timer value for the response window;
determining whether the timer for the response window expires and a response for the transmitting the one or more preambles is received before the response window expires;
incrementing the preamble transmission counter in response to the timer for the response window expiring and the response being not received before the timer for the response window expired;
determining whether the preamble transmission counter exceeds the first number; and
determining the failure of the beam failure recovery in response to the preamble transmission counter exceeding the first number.

### Claim 8 (depends on 1)

The method of claim 1,
wherein detecting the one or more beam failure instances based on the plurality of the reference signals for the beam failure detection comprises:
determining whether a radio link quality of the plurality of the reference signals is worse than a first threshold; and
detecting the one or more beam failure instances in response to the radio link quality of the plurality of the reference signals being worse than the first threshold.

### Claim 9 (depends on 8)

The method of claim 8, wherein the radio link quality comprises a value of a block error rate (BLER).

### Claim 10

A wireless device comprising:
a transceiver; and
at least one processor configured to:
control the transceiver to receive one or more RRC messages comprising configuration parameters for a beam failure recovery, wherein the configuration parameters comprises a plurality of reference signals for a beam failure detection, a second number of beam failure instances, a timer value for a response window, and a first number for preamble transmissions,
detect one or more beam failure instances based on the plurality of the reference signals for the beam failure detection,
determine a beam failure based on a number of detection of the one or more beam failure instances reaching the second number,
initiate a random access procedure for the beam failure recovery,
control the transceiver to transmit one or more preambles in response to initiating a beam failure recovery,
determine a failure of the beam failure recovery based on a number of transmissions of the one or more preambles exceeding the first number,
determine a radio link failure in response to the failure of the beam failure recovery,
store a cause of the radio link failure as the failure of the beam failure recovery, and
start, based on the determination of the radio link failure, a radio resource control (RRC) connection re-establishment procedure.

### Claim 11 (depends on 10)

The wireless device of claim 10, wherein the at least one processor is further configured to control the transceiver to transmit, based on the RRC connection re-establishment procedure, one or more RRC messages comprising a radio link failure report including the cause of the radio link failure.

### Claim 12 (depends on 11)

The wireless device of claim 11, wherein the at least one processor is further configured to indicate first information to an RRC layer of the wireless device in response to the number of transmissions of the one or more preambles being greater the first number, wherein the first information comprises an indication of the failure of the beam failure recovery.

### Claim 13 (depends on 12)

The wireless device of claim 12, wherein the radio link failure report comprises one or more parameters indicating the failure of the beam failure recovery is the cause of the radio link failure.

### Claim 14 (depends on 10)

The wireless device of claim 10, wherein the at least one processor is further configured to monitor a downlink control channel in a control resource set for reception of a response to transmission of the one or more preambles.

### Claim 15 (depends on 10)

The wireless device of claim 10, wherein the at least one processor is further configured to set a preamble transmission counter to an initial value.

### Claim 16 (depends on 15)

The wireless device of claim 15, wherein the at least one processor is further configured to:
start a timer for the response window based on the timer value for the response window,
determine whether the timer for the response window expires and a response for the transmitting the one or more preambles is received before the timer for the response window expires,
increment the preamble transmission counter in response to the timer for the response window expiring and the response being not received before the timer for the response window expired,
determine whether the preamble transmission counter exceeds the first number; and
determine the failure of the beam failure recovery in response to the preamble transmission counter exceeding the first number.

### Claim 17 (depends on 10)

The wireless device of claim 10, wherein the at least one processor is further configured to:
determine whether a radio link quality of the plurality of the reference signals is worse than a first threshold, and
detect the one or more beam failure instances in response to the radio link quality of the plurality of the reference signals being worse than the first threshold.

### Claim 18

A system comprising:
a wireless device comprising:
a first transceiver; and
at least one first processor configured to:
control the first transceiver to receive one or more RRC messages comprising configuration parameters of a beam failure recovery, wherein the configuration parameters comprises a plurality of reference signals for a beam failure detection, a second number of beam failure instances, a timer value for a response window, and a first number for preamble transmissions,
detect one or more beam failure instances based on the plurality of the reference signals for the beam failure detection,
determine a beam failure based on a number of detection of the one or more beam failure instances reaching the second number,
initiate a random access procedure for the beam failure recovery,
control the first transceiver to transmit one or more preambles in response to initiating a beam failure recovery,
determine a failure of the beam failure recovery based on a number of transmissions of the one or more preambles exceeding the first number,
determine a radio link failure in response to the failure of the beam failure recovery, and
start, based on the radio link failure, a radio resource control (RRC) connection re-establishment procedure, and
a base station comprising:
a second transceiver; and
at least one second processor configured to:
control the second transceiver to transmit the one or more RRC messages comprising the configuration parameters of the beam failure recovery, and
control the second transceiver to receive the one or more preambles.