Method and apparatus for accessing channel in WLAN system

• US 9,615,286 B2
• Filed: 04/02/2013
• Issued: 04/04/2017
• Est. Priority Date: 04/02/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Choi, Jinsoo, Han, Seunghee, Kwak, Jinsam, Seok, Yongho, Kim, Jeongki
• Primary Examiner(s): Scheibel, Robert C
• Application Number:
  US14/389,953
• Publication Number:
  US 20150334592A1
• Time in Patent Office: 1,463 Days
• Field of Search: None
• CPC Class Codes: H04W 28/0221 power availability or consumption
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0816 with collision avoidance
• 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, disclosed are a method and an apparatus for accessing a channel in a WLAN system. A method for accessing the channel from a station (STA) in the wireless communication system, according to one embodiment of the present invention, comprises a step of transmitting a power save-poll (PS-poll) for channel accessing from a listening interval to an access point, wherein the station operates in a non-traffic indication map (TIM) mode which is not limited by a TIM element that is transmitted from the access point, and wherein the time of transmission of the PS-poll is not limited by the TIM element.

Claims

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

transmitting listening interval information to an access point (AP)

wherein the listening interval is a period that a power save STA wakes up and listens to a beacon frame from an access point (AP),

performing the channel access based on a mode of the STA,

wherein the beacon frame including a traffic indication map (TIM) element is received during the listening interval when the STA is in a TIM mode,

wherein a power save (PS)-Poll for channel access is received by the AP during the listening interval when the STA is in a non-TIM mode,

wherein the STA in the non-TIM mode transmits the PS-Poll without receiving the beacon frame including the TIM element from the AP during every listening interval.

2. The method according to claim 1, wherein a start time of the listening interval is one of a time for the STA to transmit power management mode setting information to the AP and a time for the STA to receive a response frame in response to the setting information.

3. The method according to claim 1, wherein the STA comprises a sensor type STA.

4. The method according to claim 1, wherein the STA in the non-TIM mode transmits the PS-Poll during every listening interval until the transmission of the PS-Poll is successful,

wherein, if the transmission of the PS-Poll continuously fails in a predetermined number of listening intervals, the STA transmits the PS-Poll between the end of a first listening interval and the start of a second listening interval,

wherein the first listening interval is the last listening interval where the transmission of the PS-Poll has failed, and

wherein the second listening interval is a next listening interval after the first listening interval.

5. The method according to claim 4, wherein the prior time is a value set through a system parameter or a value preset through a management process between the STA and the AP.

6. The method according to claim 1, wherein, even if the transmission of the PS-Poll is performed at a second time later than a first time of the listening interval, a transmission time of a next PS-Poll is estimated from the first time rather than from the second time.

7. A station (STA) for performing channel access in a wireless communication system comprising:

a transceiver; and

a processor configured to control the transceiver,

wherein the processor further;

transmits listening interval information to an access point (AP),

wherein the listening interval is a period that a power save STA wakes up and listens for a beacon frame from an access point (AP),

performs channel access based on a mode of the STA,

controls the transceiver to receive a beacon frame including a traffic indication map (TIM) element during the listening interval when the STA is in a TIM mode, and

controls the transceiver to transmit a power save (PS)-poll for channel access to the AP during the listening interval when the STA is in a non-TIM mode,

wherein the STA in the non-TIM mode transmits the PS-Poll without receiving the beacon frame including TIM element from the AP in every listening interval.

8. The STA according to claim 7, wherein the processor sets one of a time to transmit power management mode setting information to the AP and a time to receive a response frame in response to the setting information as a start time of the listening interval.

9. The STA according to claim 7, wherein the STA comprises a sensor type STA.

10. The STA according to claim 7, wherein the PS-Poll is transmitted during every listening interval in the non-TIM mode until the transmission of the PS-Poll is successful,

wherein the processor controls the transceiver to transmit the PS-Poll between the end of a first listening interval and the start of a second listening interval when the transmission of the PS-Poll continuously fails in a predetermined number of listening intervals,

wherein the first listening interval is the last listening interval where the transmission of the PS-Poll has failed, and

wherein the second listening interval is a next listening interval after the first listening interval.

11. The STA according to claim 10, wherein the prior time is a value set through a system parameter or a value preset through a management process between the STA and the AP.

12. The STA according to claim 7, wherein, even if transmission of the PS-Poll is performed at a second time later than a first time of the listening interval, the processor computes a transmission time of a next PS-Poll from the first time rather than from the second time.