METHOD FOR PERFORMING RANDOM ACCESS IN WIRELESS LAN SYSTEM AND DEVICE FOR SAME

• US 20180146476A1
• Filed: 05/20/2016
• Published: 05/24/2018
• Est. Priority Date: 05/20/2015
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: KIM, Jeongki, RYU, Kiseon, CHO, Hangyu
• Granted Patent: US 10,397,916 B2
• Time in Patent Office: Days
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/008 with additional processing of random access related information at receiving side
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0841 with collision treatment
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The present invention relates to a method for performing random access in a wireless LAN system and a device for same. To this end, a station receives from an AP a frame comprising resource allocation information for random access and performs backoff, on the basis of a predetermined contention window size, in resources allocated on the basis of the resource allocation information for random access. In addition, the station transmits, at a first point in which a backoff counter reaches 0, a second frame by means of randomly selected resources which have been randomly selected among the resources that have been allocated as specified, wherein the STA performs clear channel assessment (CCA) for the resources that have been allocated on the basis of the resource allocation information for random access and thus controls the transmission of the second frame by means of the randomly selected resources on the basis of a CCA result.

Claims

1. A method of performing random access to an access point (AP) by a station (STA) operating in a wireless local area network (WLAN) system, the method comprising:

receiving a first frame including resource allocation information for random access from the AP;

performing backoff based on a predetermined contention window size in resources allocated according to the resource allocation information for random access; and

transmitting a second frame through a randomly selected resource from among the resources allocated according to the resource allocation information for random access at a first timing at which a backoff count reaches 0,

wherein the STA performs clear channel assessment (CCA) for the resources allocated according to the resource allocation information for random access to adjust transmission of the second frame through the randomly selected resource according to a result of CCA.

2. The method according to claim 1, further comprising, when the randomly selected resource at the first timing is busy as the result of CCA not transmitting the second frame at the first timing.

3. The method according to claim 2, further comprising:

receiving a third frame including resource allocation information for subsequent random access from the AP; and

transmitting, at a second timing, the second frame, which has not been transmitted at the first timing, through a second randomly selected resource from among resources allocated according to the resource allocation information for subsequent random access based on the third frame.

4. The method according to claim 3, wherein when the third frame is received, the second timing is determined while the backoff count is maintained at 0.

5. The method according to claim 1, wherein when the randomly selected resource at the first timing is determined to be busy as the result of CCA, the randomly selected resource is adjusted as one of resources which are idle at the first timing according to a predetermined rule.

6. The method according to claim 5, wherein the adjusted resource is determined to be a first resource which is idle among resource units subsequent to the randomly selected resource.

7. The method according to claim 1, wherein the randomly selected resource is randomly selected from among resources which are idle as the result of CCA.

8. The method according to claim 1, wherein the predetermined contention window size is determined in correspondence to the number of resource units of the resources allocated according to the resource allocation information for random access.

9. The method according to claim 1, further comprising:

setting a random access threshold value corresponding to the number of resource units which are idle among the resources allocated according to the resource allocation information for random access; and

not attempting to perform random access in the resources allocated according to the resource allocation information for random access of the first frame, when a randomly selected value within the predetermined contention window size is larger than the random access threshold value.

10. A station (STA) for operating in a wireless local area network (WLAN) system, the STA comprising:

a transceiver configured to receive a first frame including resource allocation information for random access from an access point (AP) and transmit a second frame through a randomly selected resource from among resources allocated according to the resource allocation information for random access; and

a processor connected to the transceiver and is configured to;

perform backoff based on a predetermined contention window size in the resources allocated according to the resource allocation information for random access, and

control the transceiver to transmit the second frame through the randomly selected resource at a first timing at which a backoff count reaches 0,

wherein the processor is further configured to perform clear channel assessment (CCA) for the resources allocated according to the resource allocation information for random access to adjust transmission of the second frame through the randomly selected resource according to a result of CCA.

11. The STA according to claim 10, wherein, when the randomly selected resource at the first timing is busy as the result of CCA, the processor is further configured to control the transceiver not to transmit the second frame at the first timing.

12. The STA according to claim 11, wherein, when the transceiver receives a third frame including resource allocation information for subsequent random access from the AP;

the processor is further configured to control the transceiver to transmit, at a second timing, the second frame, which has not been transmitted at the first timing, through a second randomly selected resource from among resources allocated according to the resource allocation information for subsequent random access based on the third frame.

13. The STA according to claim 12, wherein the processor is further configured to determine the second timing while the backoff count is maintained at 0 when the transceiver receives the third frame.

14. The STA according to claim 10, wherein the processor is further configured to adjust the randomly selected resource as one of resources which are idle at the first timing according to a predetermined rule when the randomly selected resource at the first timing is determined to be busy as the result of CCA.

15. The STA according to claim 10, wherein the processor is further configured to randomly select the randomly selected resource from among resources which are idle as the result of CCA.