DOWNLINK ACKNOWLEDGMENT IN RESPONSE TO UPLINK MULTIPLE USER TRANSMISSION

• US 20160029373A1
• Filed: 07/28/2015
• Published: 01/28/2016
• Est. Priority Date: 07/28/2014
• Status: Active Grant

• Current Assignee: Atlas Global Technologies LLC (Acacia Research Corporation)
• Original Assignee: Newracom Inc.
• Inventors: SEOK, Yongho
• Granted Patent: US 9,866,359 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The present invention provides a method and apparatus for transmitting a downlink ACK in response to an uplink multi-user transmission in a HE WLAN. In an aspect of the present invention, a method for transmitting an ACK in response to uplink data received from a plurality of STAs by an AP in a WLAN may be provided. The method may include transmitting a frame triggering transmission of a plurality of uplink data units from the plurality of STAs to the plurality of STAs, receiving a PPDU frame including a plurality of uplink data units from the plurality of STAs a predetermined IFS after transmitting the trigger frame, and transmitting an ACK frame including ACKs for the plurality of data units from the plurality of STAs.

Claims

1. A method for transmitting an ACKnowledgement (ACK) in response to uplink data received from a plurality of Stations (STAs) by an Access Point (AP) in a Wireless Local Area Network (WLAN), the method comprising:

transmitting, to the plurality of STAs, a frame triggering transmission of a plurality of uplink data units from the plurality of STAs;

receiving a Physical layer Protocol Data Unit (PPDU) frame including a plurality of uplink data units from the plurality of STAs a predetermined Inter-Frame Space (IFS) after transmitting the trigger frame; and

transmitting an ACK frame including ACKs for the plurality of data units from the plurality of STAs.

2. The method according to claim 1, wherein when a data unit is received without an error from at least one of the plurality of STAs, a frame exchange procedure initiated by the trigger frame is determined to be successful.

3. The method according to claim 1, wherein when a frame exchange procedure initiated by the trigger frame is determined to be successful, channel access of the AP is performed using a first IFS, and

when the frame exchange procedure initiated by the trigger frame is determined to be failed, channel access of the AP is performed using a second IFS, and

wherein the first IFS is shorter than the second IFS.

4. The method according to claim 1, wherein when the PPDU frame is determined to be received without an error, channel access of the AP is performed using a Distributed coordination function Inter-Frame Space (DIFS).

5. The method according to claim 1, wherein when all of the data units received from the plurality of STAs have errors, reception of the PPDU frame at the AP is determined to have an error.

6. The method according to claim 5, wherein when the reception of the PPDU frame is determined to have an error, channel access of the AP is performed using an Extended Inter-Frame Space (EIFS).

7. The method according to claim 1, wherein information transmitted from a PHYsical (PHY) layer of the AP to a Medium Access Control (MAC) layer of the AP includes information indicating end of reception, and

wherein the information indicating end of reception includes a parameter indicating whether a reception error occurs to each of the plurality of STAs or each of the plurality of subchannels.

8. The method according to claim 7, wherein the information indicating end of reception is a PHY-RXEND.indication primitive and the parameter indicating whether a reception error occurs to each of the plurality of STAs or each of the plurality of subchannels is a USER_INDEX parameter.

9. The method according to claim 1, wherein the ACK frame includes one or more ACK fields respectively corresponding to one or more of the plurality of STAs, and

wherein each of the one or more ACK fields includes a first subfield including identification information about an STA, a second subfield indicating block ACK or ACK, and a third subfield indicating a Traffic Identifier (TID).

10. The method according to claim 9, wherein when the second subfield included in the ACK field indicates block ACK, the ACK field includes block ACK bitmap information and block ACK starting sequence control information, and

wherein when the second subfield included in the ACK field indicates ACK, the ACK field does not include the block ACK bitmap information and the block ACK starting sequence control information.

11. A method for receiving an ACKnowledgement (ACK) in response to uplink data transmitted to an Access Point (AP) by a Station (STA) in a Wireless Local Area Network (WLAN), the method comprising:

receiving, from the AP, a frame triggering transmission of a plurality of uplink data units from the STA and one or more other STAs;

transmitting a Physical layer Protocol Data Unit (PPDU) frame including an uplink data unit of the STA a predetermined Inter-Frame Space (IFS) after receiving the trigger frame, when the other one or more STAs transmit one or more data units; and

receiving an ACK frame including ACKs for the plurality of data units from the plurality of STAs.

12. The method according to claim 11, wherein when the AP receives a data unit from at least one of the plurality of STAs without an error, a frame exchange procedure initiated by the trigger frame is determined to be successful.

13. The method according to claim 11, wherein when the AP determines that a frame exchange procedure initiated by the trigger frame is successful, an IFS for channel access of the AP is set to a first IFS, and

when the AP determines that the frame exchange procedure initiated by the trigger frame is failed, the IFS for the channel access of the AP is set to a second IFS, and

wherein the first IFS is shorter than the second IFS.

14. The method according to claim 11, wherein when the PPDU frame is determined to be received without an error, an IFS for channel access of the AP is set to a Distributed coordination function Inter-Frame Space (DIFS).

15. The method according to claim 11, wherein when all of the data units received from the plurality of STAs have errors, reception of the PPDU frame at the AP is determined to have an error.

16. The method according to claim 15, wherein when the reception of the PPDU frame is determined to have an error, an IFS for channel access of the AP is set to an Extended Inter-Frame Space (EIFS).

17. The method according to claim 11, wherein an ACKTimeout for the STA is determined by the following equation,

ACKTimeout=aSIFSTime+aSlotTime+aPHY-RX-Start-Delay+X

where aSIFSTime is a Short Inter-Frame Space (SIFS), aSlotTime is a slot time, aPHY-RX-Start-Delay is a delay time until a reception time at a physical layer, X is an ACKTimeout correction value.

18. The method according to claim 11, wherein the ACK frame includes one or more ACK fields corresponding to one or more of the plurality of STAs, respectively, and

wherein each of the one or more ACK fields includes a first subfield including identification information about an STA, a second subfield indicating block ACK or ACK, and a third subfield indicating a Traffic Identifier (TID).

19. The method according to claim 18, wherein when the second subfield included in the ACK field indicates block ACK, the ACK field includes block ACK bitmap information and block ACK starting sequence control information, and

wherein when the second subfield included in the ACK field indicates ACK, the ACK field does not include the block ACK bitmap information and the block ACK starting sequence control information.