DEVICE AND METHOD FOR CONTROLLING SLOT-BASED CHANNEL ACCESS IN WIRELESS LAN SYSTEM, AND SLOT-BASED CHANNEL ACCESS TERMINAL IN WIRELESS LAN

• US 20150327262A1
• Filed: 06/19/2013
• Published: 11/12/2015
• Est. Priority Date: 06/19/2012
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: KWON, Hyoung Jin, LEE, Jae Seung, CHEONG, Min Ho, YU, Hee Jung, LEE, Sok Kyu
• Granted Patent: US 9,781,741 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

An apparatus and a method of controlling slot-based channel access by an access point (AP) to manage a network in a wireless local area network (WLAN) environment and a slot-based channel access terminal are disclosed. A slot-based channel access control apparatus of a WLAN system according to an exemplary embodiment determines one of each terminal and a group of terminals as a slot allocation target, allocates a slot defined in a beacon interval to the determined terminal or group to distinguish channel access time, and transmits a beacon including information on the allocated slot.

Claims

1. A slot-based channel access control apparatus in a wireless local area network (WLAN) system, the apparatus comprising:

a controller to determine one of each terminal and a group of terminals as a slot allocation target;

an allocation unit to allocate a slot defined in a beacon interval to the determined terminal or group to distinguish channel access time; and

a transmission unit to transmit a beacon comprising information on the allocated slot.

2. The apparatus of claim 1, wherein the information on the allocated slot comprises allocation control information, an association identification (AID), a start slot ID and allocation duration information.

3. The apparatus of claim 1, wherein the information on the allocated slot comprises an AID and a start slot ID when the slot is allocated to each terminal and resources are successively allocated to each terminal,

wherein the information on the allocated slot comprises a start slot ID according to an order of being set to “

1”

bit in a traffic indication map (TIM) when resources are allocated only to terminals set to “

1”

bit in the TIM.

5. The apparatus of claim 1, wherein the terminals comprise a TIM station (STA) that checks the beacon and verifies buffered downlink data or a non-TIM STA that does not verify the beacon or buffered downlink data of a TIM broadcast frame.

8. The apparatus of claim 5, further comprising a reception unit to receive, from the non-TIM STA, whether to support a target wake time (TWT) function allocated as wakeup time of the non-TIM STA through an association request frame, wherein the allocation unit allocates an AID of a TWT STA supporting the TWT function to a non-TIM STA group supporting the TWT function.

9. The apparatus of claim 5, further comprising a setup unit to set up a period comprising an entire TWT period to be allocated as restricted access window (RAW) when the beacon interval comprises a TWT to be allocated by the allocation unit, wherein the transmission unit transmits RAW related information to be included in the beacon,

wherein when a plurality of PAWs comprises an overlapping period, the setup unit sets up a network allocation vector (NAV) or access priority by RAW group so that the terminals or group does not conduct channel access in the overlapping period.

10. The apparatus of claim 9, wherein the RAW related information is defined as an RAW parameter set information element (RPS IE),

wherein the RPS IE comprises RAW group information, RAW start time information, RAW duration information and slot information,

wherein the RAW group information comprises a page ID, a block offset and a block range.

12. The apparatus of claim 9, wherein the TIM STA receiving the beacon comprising the RAW related information does not conduct channel access in the RAW.

13. The apparatus of claim 10, wherein when the RPS IE comprises an indicator showing that the RAW is allocated to the non-TIM STA, the RAW group information and slot information are omitted.

14. The apparatus of claim 1, wherein the allocation unit allocates a TWT identified as a flow identifier to each flow when each terminal comprises a plurality of flows with different traffic properties, and allocates a plurality of AIDs to each terminal.

15. The apparatus of claim 10, wherein when the RPS IE comprises an indicator showing that the RAW is allocated to the non-TIM STA, and when the RAW group information is omitted, the TIM STA listening to the RPS IE does not access a channel set in a channel (CH) indication field during a time of a RAW duration from RAW start time,

wherein when the allocated TWT is included during the time of the RAW duration from the RAW start time, a TWT STA listening to the RPS IE conducts channel access at the allocated TWT.

17. The apparatus of claim 8, further comprising a scheduling unit to schedule an RAW for the unscheduled active polling STA in advance,

wherein when the reception unit receives a PS-poll frame from the unscheduled active polling STA, the transmission unit transmits RAW related information scheduled in advance to the unscheduled active polling STA,

wherein the RAW related information is defined as an RPS IE,

wherein the RPS IE comprises RAW group information, RAW start time information, RAW duration information, an indicator showing that the RAW is allocated to the non-TIM STA and an indicator showing that the RAW is allocated to the unscheduled active polling STA.

20. The apparatus of claim 1, wherein the allocation unit periodically allocates resources for the non-TIM STA set to be a RAW, as a periodic RAW (PRAW), to the terminals or group, and the transmission unit transmits a beacon comprising information on the allocated PRAW.

21. The apparatus of claim 20, wherein the information on the PRAW is defined as an RPS IE,

wherein the RPS IE comprises an indicator showing that the allocated RAW is the PRAW, a PRAW period and PRAW start time information,

wherein the transmission unit transmits the RPS IE to be included in a long beacon,

wherein the PRAW start time information comprises relative PRAW start time calculated using an offset that is a number of beacon intervals in which a first PRAW appears from the long beacon,

wherein the PRAW start time information comprises absolute PRAW start time calculated using a timing synchronization function (TSF).

25. The apparatus of claim 1, wherein the allocation unit allocates the slot to the terminals or group associated with a relay STA from the relay STA using a PRAW, and the transmission unit transmits a beacon comprising information on the allocated PRAW,

wherein the information on the allocated PRAW comprises an indicator showing that the PRAW is allocated to a single terminal and an AID of the single terminal.

27. The apparatus of claim 25, wherein the allocation unit allocates different start times of first PRAWs allocated to a plurality of relay STAs, so that resources are allocated to different relay STAs through time sharing.

28. The apparatus of claim 1, further comprising a detection unit to detect a channel during a data sensing time set in the allocated slot, and

a determination unit to determine that the allocated slot is in an idle state when the channel is not detected during the data sensing time,

wherein the transmission unit transmits information indicating that the allocated slot is in the idle state to a terminal to which the slot is not allocated.

4. (canceled)

6-7. -7. (canceled)

11. (canceled)

16. (canceled)

18-19. -19. (canceled)

22-24. -24. (canceled)

26. (canceled)

29. (canceled)

30. A slot-based channel access terminal in a wireless local area network (WLAN) system, the terminal comprising:

a reception unit to receive a beacon comprising information on a slot allocated from an access point (AP); and

a channel access unit to conduct channel access in the slot based on the information on the allocated slot.

31. The terminal of claim 30, further comprising a controller to set a network allocation vector (NAV) of transmission opportunity (TxOP) in the slot based on data capacity,

wherein the reception unit receives information on a restricted access window (RAW) comprising successively allocated slots from the AP, and the channel access unit conducts channel access in the slot based on RAW group information, RAW start time information, RAW duration information and slot information comprised in the information on the RAW.

32. (canceled)

33. A slot-based channel access control method in a wireless local area network (WLAN) system, the method comprising:

determining one of each terminal and a group of terminals as a slot allocation target;

allocating a slot defined in a beacon interval to the determined terminal or group to distinguish channel access time; and

transmitting a beacon comprising information on the allocated slot.