# US 12,120,746 B2 · Channel sensing for physical random access channel (PRACH) signals in new radio (NR) systems operating in the unlicensed spectrum

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- Number: US 12,120,746 B2
- Document ID: US12120746B2
- Status: Granted
- Kind: B2
- Application number: 17/441,122
- Filed: 2020-06-19
- Published: 2022-05-26
- Granted: 2024-10-15
- Earliest claimed: 2019-06-19
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Carlos H. Aldana; Salvatore Talarico; Yongjun Kwak; Lopamudra Kundu
- Web page: https://patentgrep.com/patent/US12120746B2

## CPC

- H04W 74/004: {in the uplink, i.e. towards network}
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04W 74/006: {in the downlink, i.e. towards the terminal}
- H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA]
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A user equipment (UE), or other network component can operate to configure channel occupancy time (COT) sharing in random access procedures involving the unlicensed spectrum. At least some of the messages for the procedures can share a COT by configuring one or more gaps or listen-before-talk (LBT) procedures based on the gap or whether the COT sharing is UE or gNB initiated. Some configurations can depend on a location in the random access procedure that COT sharing is acquired.

## Claims

### Claim 1

An apparatus employed in a user equipment (UE), comprising processing circuitry configured to:
generate and cause transmission of a first message comprising a preamble of a random access channel (RACH);
receive, from a base station, a second message indicating a reception of the preamble and comprising a time-adjustment command and a scheduling grant via a physical downlink channel;
generate and cause transmission of a third message based on a resource indicated by the scheduling grant of the second message;
receive, from the base station, a fourth message comprising contention resolution information; and
generate a hybrid automatic repeat request (HARQ) feedback based on the fourth message,
wherein the third message includes a listen-before-talk (LBT) indication that indicates which LBT type the base station is to perform, and wherein the LBT indication comprises one bit of an uplink control information (UCI).

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the LBT indication comprises two bits of an uplink control information (UCI).

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the second message comprises a random access response (RAR) message.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein a channel access priority class (CAPC) is indicated by the third message. .

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the processing circuitry is further configured to configure the third message to share a channel occupancy time (COT) with the second message based on a gap therebetween that is sixteen microseconds or twenty-five microseconds.

### Claim 6

A method for a base station, comprising:
receiving a first message from a user equipment (UE), the first message comprising a preamble of a random access channel (RACH) configured to perform a random access procedure;
generating and transmitting a second message that indicates a reception of the preamble and comprising a time-adjustment command and a scheduling grant via a physical downlink channel for configuring a third message;
receiving the third message from the UE based on a resource indicated by the scheduling grant of the second message;
generating and transmitting a fourth message to transfer the UE to a connected state; and
receiving a HARQ feedback from the UE based on the fourth message,
wherein the third message includes a listen-before-talk (LBT) indication that indicates which LBT type the base station is to perform,
wherein the third message comprises a UCI that includes two bits that comprise the LBT indication.

### Claim 7 (depends on 6)

The method of claim 6, wherein the second message comprises random access response (RAR).

### Claim 8

A method for a user equipment (UE), comprising:
generating a first message comprising a preamble of a random access channel (RACH);
receiving a second message indicating a reception of the preamble and comprising a scheduling grant via a physical downlink channel;
generating a third message based on a resource indicated by the scheduling grant of the second message;
receiving a fourth message comprising contention resolution information; and
generating a hybrid automatic repeat request (HARQ) feedback based on the fourth message;
wherein the third message includes a listen-before-talk (LBT) indication that indicates which LBT type a base station is to perform, and
wherein at least two of: the first message, the second message, the third message, the fourth message, or the HARQ feedback share a channel occupancy time (COT) in a random access procedure, wherein the HARQ feedback is transmitted within 16 microseconds of the fourth message.

### Claim 9 (depends on 8)

The method of claim 8, wherein the LBT indication comprises two bits of an uplink control information (UCI).

### Claim 10 (depends on 8)

The method of claim 8, wherein the LBT indication comprises one bit of an uplink control information (UCI).

### Claim 11 (depends on 8)

The method of claim 8, wherein the second message comprises a random access response (RAR) message.

### Claim 12 (depends on 8)

The method of claim 8, wherein a channel access priority class (CAPC) is indicated by the third message.

### Claim 13 (depends on 1)

The apparatus of claim 1, wherein the one bit in the UCI that indicates LBT is a channel occupancy time (COT) sharing bit.

### Claim 14 (depends on 6)

The method of claim 6, wherein a first bit of the two bits that comprise the LBT indication is a channel occupancy time (COT) sharing bit.

### Claim 15 (depends on 8)

The method of claim 8, wherein the third message includes a COT sharing bit.