METHOD AND APPARATUS FOR ACCESSING CHANNELS IN WIRELESS LAN SYSTEM

• US 20150009878A1
• Filed: 02/04/2013
• Published: 01/08/2015
• Est. Priority Date: 02/02/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Jeongki, Seok, Yongho, Kwak, Jinsam, Choi, Jinsoo
• Granted Patent: US 9,426,736 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 52/0209 in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention relates to a wireless communication system, and more specifically, to a method and apparatus for accessing channels in a wireless LAN system. The method for accessing channels in a station (STA) of the wireless communication system according to one embodiment of the present invention comprises the steps of transmitting a first frame of a channel access request to an access point (AP); and receiving, from the AP, a second frame related to whether access to the channel is allowed in response to the first frame, wherein the second frame can include a value for a channel access start offset with respect to the STA.

Claims

1. A method of performing channel access at a station (STA) in a wireless communication system, the method comprising:

transmitting a power save (PS)-Poll frame to an access point (AP); and

receiving, from the AP, an acknowledgment frame in response to the PS-Poll frame,

wherein the acknowledgment frame includes a value of a channel access start offset for the STA.

2. The method according to claim 1, wherein the value of the channel access start offset determines when the STA wakes up again after entering a sleep state.

3. The method according to claim 1, wherein the PS-Poll frame includes at least one of an association identifier (AID) of the STA, a group ID assigned to the STA or uplink (UL)/downlink (DL) channel access request indicator information.

4. The method according to claim 1, wherein the acknowledgment frame includes at least one of a timestamp, acknowledgement (ACK), granted channel access duration, a current access group number, a current channel access group identifier, a next access group start offset, a channel access start offset or a new STA identifier.

5. The method according to claim 4, wherein the channel access start offset is one of a downlink data reception start time of the STA, a start time of a channel access interval at which uplink data transmission of the STA is granted, a next beacon transmission time, a next beacon transmission start time for a group corresponding to the STA, or a channel access start time of a group assigned to the STA.

6. The method according to claim 1, wherein:

the acknowledgment frame includes response type information, and

the response type information indicates one of channel access allowance, channel access rejection or STA identifier reassignment.

9. The method according to claim 1, wherein the PS-Poll frame is transmitted if the STA is switched from a sleep state to an awake state.

10. The method according to claim 1, wherein, without receiving a beacon including a traffic indication map (TIM), transmission of the PS-Poll frame is allowed in an awake state of the STA.

11. The method according to claim 1, wherein whether channel access is granted is determined by the AP based on whether a page identifier of the STA matches a page identifier related to a current channel access interval.

12. The method according to claim 1, wherein the transmitting the PS-Poll frame to the AP is performed during a channel access interval during which channel access of a group, to which the identifier of the STA belongs, is not granted.

7. (canceled)

8. (canceled)

13. A method of supporting channel access of a station (STA) in an access point (AP) of a wireless communication system, the method comprising:

receiving a power save (PS)-Poll frame from the STA; and

transmitting, to the STA, an acknowledgment frame in response to the first PS-Poll frame,

wherein the acknowledgment frame includes a value of a channel access start offset for the STA.

14. A station (STA) apparatus for performing channel access in a wireless communication system, the STA apparatus comprising:

a transceiver; and

a processor,

wherein the processor is configured to transmit a power save (PS)-Poll frame to an access point (AP) and to receive, from the AP, an acknowledgment frame related to whether channel access is granted, in response to the first PS-Poll frame, and

wherein the acknowledgment frame includes a value of a channel access start offset for the STA.

15. An access point (AP) apparatus for supporting channel access of a station (STA) in a wireless communication system, the AP apparatus comprising:

a transceiver; and

a processor,

wherein the processor is configured to receive a power save (PS)-Poll frame from the STA and to transmit, to the STA, an acknowledgment frame in response to the PS-Poll frame, and

wherein the acknowledgment frame includes a value of a channel access start offset for the STA.