METHOD AND APPARATUS FOR ACCESSING CHANNEL IN WLAN SYSTEM

• US 20150124722A1
• Filed: 04/29/2013
• Published: 05/07/2015
• Est. Priority Date: 04/28/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Seok, Yongho
• Granted Patent: US 9,451,636 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 40/244 using a network of reference devices, e.g. beaconing
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/04 Scheduled access 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, disclosed are a method and an apparatus for accessing a channel in a WLAN system. The method for accessing a channel from a station (STA) in a wireless communication system, according to one embodiment of the present invention, comprises the steps of: receiving from an access point (AP) a first frame including a traffic indication map (TIM) and a restricted access window (RAW) parameter set component; determining a RAW in which channel access of the STA is permitted, on the basis of the RAW parameter set (RPS) component; and transmitting a second frame to the AP from within the RAW that is determined, wherein the RPS component includes at least one RAW indication field, each of the at least one RAW allocation fields further includes information related to transmitting a third frame, which includes information on slot allocation, and wherein the third frame can be received by the STA from the AP at a specific time/location in accordance with the information related to transmitting the third frame.

Claims

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

receiving, from an access point, a first frame containing a traffic indication map (TIM) element and a restricted access window (RAW) parameter set element;

determining a RAW allowing channel access of the STA based on the RAW parameter set (RPS) element; and

transmitting a second frame to an access point (AP) within the determined RAW,

wherein the RPS element comprises at least one RAW assignment field,

wherein each of the at least one RAW assignment field contains information related to transmission of a third frame containing information about assignment of slots,

wherein the third frame is received from the AP by the STA at a specific time position according to the information related to transmission of the third frame.

2. The method according to claim 1, wherein the specific time position is a time position for start of a next RAW subsequent to the RAW having the second frame transmitted therein.

3. The method according to claim 2, wherein the STA wakes up and receives the third frame at the time position for start of the next RAW.

4. The method according to claim 1, wherein the third frame is a RAW announcement frame, the RAW announcement frame containing information about assignment of the slots in an RAW for transmission of the third frame.

5. The method according to claim 1, wherein, when the third frame is not transmitted by the AP, slot assignment in the RAW is determined based on an association identifier (AID) of the STA and the number of slots in the RAW.

6. The method according to claim 1, wherein each of the at least one RAW assignment field comprises a RAW group field, a RAW start time field and a RAW duration field.

7. The method according to claim 6, wherein the RAW group field indicates association identifiers (AIDs) of STAs allowed to perform channel access within the RAW,

wherein whether or not the STAs belong to a group indicated by the RAW group field is determined.

8. The method according to claim 1, wherein:

the RAW comprises at least one slot; and

each of the at least one RAW assignment field comprises a slot duration field and a cross slot boundary field.

9. The method according to claim 8, wherein the slot duration field indicates a duration of the at least one slot having the same value within the RAW.

10. The method according to claim 8, wherein the cross slot boundary field indicates whether or not transmission by the STA is allowed to cross a slot boundary.

11. The method according to claim 1, wherein each of the at least one RAW assignment field comprises a field indicating whether or not the channel access is restricted to paged STAs only.

12. The method according to claim 1, wherein the STA operates in a doze state before a time, and switches to an awake state at the time, the channel access within the RAW being allowed at the time.

13. The method according to claim 1, wherein the first frame is a beacon frame, and the second frame is a power save (PS)-Poll frame or a trigger frame.

14. The method according to claim 1, wherein the second frame is transmitted within the RAW based on enhanced distributed channel access (EDCA).

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

a transceiver; and

a processor,

wherein the processor is configured to;

receive, from an access point, a first frame containing a traffic indication map (TIM) element and a restricted access window (RAW) parameter set element using the transceiver;

determine a RAW allowing channel access of the STA based on the RAW parameter set (RPS) element; and

transmit a second frame to an access point (AP) within the determined RAW using the transceiver,

wherein the RPS element comprises at least one RAW assignment field,

wherein each of the at least one RAW assignment field contains information related to transmission of a third frame containing information about assignment of slots,

wherein the third frame is received from the AP by the STA at a specific time position according to the information related to transmission of the third frame.