Apparatus and method for controlling slot usage

• US 10,624,135 B2
• Filed: 09/27/2017
• Issued: 04/14/2020
• Est. Priority Date: 07/05/2012
• 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, Park, Jae Woo, Lee, Sok Kyu
• Primary Examiner(s): Islam, Rownak
• Application Number:
  US15/717,535
• Publication Number:
  US 20180092132A1
• Time in Patent Office: 930 Days
• Field of Search: 370338
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0891 for synchronized access
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/12 Access point controller devices

Abstract

Provided is slot use control apparatus and method, including an access point (AP) to control a slotted channel access of a station (STA) in a wireless local area network (WLAN) includes generating a synchronization (synch) frame including an identification value indicating an STA allocated to a slot, and broadcasting the generated synch frame when a channel is in an idle state at a start point of the slot.

Claims

1. A method for controlling channel access by an access point (AP) in a wireless local area network (WLAN), the method comprising:

transmitting a synchronization frame that includes a receiver address (RA) field including an identification value indicating a first station (STA), wherein the synchronization frame is transmitted if a channel is in an idle state at a time point when the first STA wakes up, the time point corresponding to a target wake time (TWT) targeted to the first STA;

configuring a response waiting time; and

when a first contention free-End (CF-End) frame is received during the response waiting time, transmitting a second CF-End frame,

wherein the first CF-End frame is transmitted by the first STA that has gained access to the channel and has no more data to transmit,

wherein the synchronization frame is distinguished from a beacon frame, and is transmitted by the AP between beacon frames to allow the first STA to access the channel,

wherein when a response frame in response to the synchronization frame is not received during the response waiting time, the AP transmits a third CF-End frame, and

wherein the second and third CF-End frames are transmitted by the AP to reset a network allocation vector (NAV) of a STA receiving the second and third CF-End frames.

2. The method of claim 1,

wherein, the AP waits for the response frame during the response waiting time after transmitting the synchronization frame.

3. The method of claim 1,

wherein the synchronization frame is transmitted in a form of a null data packet (NDP) which includes a Short Training Field (STF) field, a Long Training Field (LTF) field, a Signal (SIG) field without a Data field.

4. The method of claim 1,

wherein the RA field of the synchronization frame comprises information of at least one of a partial association identifier (AID) or a partial basic service set identifier (BSSID).

5. The method of claim 1,

wherein the synchronization frame is used for protecting the TWT for the first STA.

6. The method of claim 1,

wherein the response frame transmitted by the first STA is an uplink data frame.

7. The method of claim 6,

wherein the synchronization frame further includes a Duration field.

8. The method of claim 7,

wherein a value of the Duration field is used for transmitting the response frame by the first STA.

9. The method of claim 7,

wherein a value of the Duration field is used for setting a NAV by at least one STA other than the first STA.

10. An apparatus of an access point (AP) for controlling channel access in a wireless local area network (WLAN), the apparatus comprising:

a receiver;

a transmitter; and

a processor,

wherein the processor is configured to;

cause the transmitter to transmit a synchronization frame that includes a receiver address (RA) field including an identification value indicating a first station (STA), wherein the synchronization frame is transmitted if a channel is in an idle state at a time point when the first STA wakes up, the time point corresponding to a target wake time (TWT) targeted to the first STA,

configure a response waiting time;

cause the receiver to receive a first contention free-End (CF-End) frame during the response waiting time, and

cause the transmitter to transmit a second contention free-End (CF-End) frame when the first CF-End frame is received during the response waiting time,

wherein the first CF-End frame is transmitted by the first STA that has gained access to the channel and has no more data to transmit,

wherein the synchronization frame is distinguished from a beacon frame, and is transmitted by the AP between beacon frames to allow the first STA to access the channel,

wherein when a response frame in response to the synchronization frame is not received during the response waiting time, the AP transmits a third CF-End frame, and

wherein the second and third CF-End frames are transmitted by the AP to reset a network allocation vector (NAV) of a STA receiving the second and third CF-End frames.