# US 12,120,741 B2 · Multi-link RTS and CTS transmissions

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- Number: US 12,120,741 B2
- Document ID: US12120741B2
- Status: Granted
- Kind: B2
- Application number: 17/800,174
- Filed: 2020-12-18
- Published: 2023-03-09
- Granted: 2024-10-15
- Earliest claimed: 2020-02-18
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Insun Jang; Jeongki Kim; Jinsoo Choi; Namyeong Kim; Suhwook Kim; Sungjin Park; Taewon Song
- Web page: https://patentgrep.com/patent/US12120741B2

## CPC

- H04W 74/0816: with collision avoidance
- H04L 69/14: Multichannel or multilink protocols
- H04L 69/321: Interlayer communication protocols or service data unit [SDU] definitions; Interfaces between layers
- H04L 69/323: in the physical layer [OSI layer 1]
- H04W 76/15: Setup of multiple wireless link connections
- H04W 84/12: WLAN [Wireless Local Area Networks]
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

In a wireless local area network system, a reception multi-link device (MLD) may not transmit a CTS frame, even if the reception multi-link device receives an RTS frame via a second link, in the case that an STA operating via a first link is a TXOP responder.

## Claims

### Claim 1

A method in a wireless local area network (WLAN) system, the method comprising:
receiving, by a second station (STA) operating on a second link, a first request to send (RTS) frame on the second link, wherein the second STA is included in a receiving multi-link device (MLD), wherein the receiving MLD further includes a first STA operating on a first link, wherein the first STA is a transmission opportunity (TXOP) responder, wherein the first link and the second link are a non-simultaneous transmit and receive (STR) link pair;
skipping, by the second STA, clear to send (CTS) frame transmission for the first RTS frame, based on that the first STA is the TXOP responder; and
receiving, by the second STA, a physical protocol data unit (PPDU) on the second link.

### Claim 2 (depends on 1)

The method of claim 1, wherein the receiving MLD is a non-STR MLD which is unable to perform transmission on the first link while reception is performed on the second link.

### Claim 3 (depends on 1)

The method of claim 1, before receiving the first RTS frame on the second link, further comprising:
receiving a second RTS frame on the first link; and
transmitting a CTS frame for the second RTS frame on the first link.

### Claim 4 (depends on 1)

The method of claim 1, further comprising transmitting acknowledgement (ACK) for the PPDU on the second link.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first link and the second link are a non-STR link set which is unable to perform transmission on the first link while reception is performed on the second link.

### Claim 6 (depends on 1)

The method of claim 1, further comprising transmitting information related to STR capability of the first link and second link.

### Claim 7

A receiving multi-link device (MLD) used in a wireless local area network (WLAN) system, the receiving MLD comprising:
a first station (STA) operating on a first link; and
a second STA operating on a second link,
wherein the first STA is a transmission opportunity (TXOP) responder, and
wherein the first link and the second link are a non-simultaneous transmit and receive (STR) link pair,
wherein the receiving MLD is adapted to:
receive, by the second STA, a first request to send (RTS) frame on the second link;
skip, by the second STA, clear to send (CTS) frame transmission for the first RTS frame, based on that the first STA is the TXOP responder; and
receive, by the second STA, a physical protocol data unit (PPDU) on the second link.

### Claim 8 (depends on 7)

The receiving MLD of claim 7, wherein the receiving MLD is a non-STR MLD which is unable to perform transmission on the first link while reception is performed on the second link.

### Claim 9 (depends on 7)

The receiving MLD of claim 7, wherein, before receiving the first RTS frame on the second link, the receiving MLD is further adapted to:
receive a second RTS frame on the first link; and
transmit a CTS frame for the second RTS frame on the first link.

### Claim 10 (depends on 7)

The receiving MLD of claim 7, wherein the receiving MLD is further adapted to transmit acknowledgement (ACK) for the PPDU on the second link.

### Claim 11 (depends on 7)

The receiving MLD of claim 7, wherein the first link and the second link are a non-STR link set which is unable to perform transmission on the first link while reception is performed on the second link.

### Claim 12 (depends on 7)

The receiving MLD of claim 7, further comprising transmitting information related to STR capability of the first link and second link.