ACK policy for uplink and downlink MU PPDU
A network device is to function as a station (STA) in a Wireless Local Area Network (WLAN) that acknowledges a downlink (DL) multi-user (MU) physical layer (PHY) Protocol Data Unit (PPDU) transmitted by an access point (AP). The network device includes one or more processors that are configured to cause the network device functioning as the STA to perform operations including decoding a frame from the DL MU PPDU, determining whether an ACK Policy field of the frame is set to a binary value of ‘01’, determining whether trigger information for an uplink (UL) MU transmission has been obtained from the DL MU PPDU, and responsive to a determination that the ACK Policy filed of the frame is set to the binary value of ‘01’ and the trigger information has been obtained from the DL MU PPDU, transmitting a trigger-based immediate acknowledgement frame to the AP.
1. A network device to function as a station (STA) in a Wireless Local Area Network (WLAN), the STA configured to acknowledge a downlink (DL) multi-user (MU) physical layer (PHY) Protocol Data Unit (PPDU) transmitted by an access point (AP), comprising:
one or more memories; and
one or more processors coupled to the one or more memories, the one or more processors configured to cause the network device functioning as the STA to perform operations comprising:
receiving the DL MU PPDU;
decoding a frame from the DL MU PPDU;
determining whether an ACK Policy field of the frame is set to a binary value of ‘01’, wherein the binary value of ‘01’ indicates to the STA to provide a trigger-based immediate acknowledgement;
determining whether a trigger information for an uplink (UL) MU transmission has been obtained from the DL MU PPDU;
responsive to the determination that the ACK Policy field of the frame is set to the binary value of ‘01’ and a determination that the trigger information has been obtained from the DL MU PPDU, transmitting a trigger-based immediate acknowledgement frame to the AP, according to the trigger information; and
responsive to the determination that the ACK Policy field of the frame is set to the binary value of ‘01’ and a determination that the trigger information has not been obtained from the DL MU PPDU, refraining from transmitting the trigger-based immediate acknowledgement frame to the AP.
2. The network device of claim 1 , wherein the binary value of ‘01’ is a reserved value for acknowledgement in a Power Save Multi-Poll (PSMP) context.
3. The network device of claim 2 , wherein the ACK Policy field set to the binary value of ‘01’ in the PSMP context indicates to the STA that a response frame to a received frame is allowed but is neither an acknowledgement frame nor any data frame of subtype Contention Free-Acknowledgement (+CF-Ack) when bit 6 of a frame control field is set to ‘1’.
4. The network device of claim 3 , wherein the ACK Policy field set to the binary value of ‘01’ in the PSMP context indicates to the STA that an acknowledgment for a frame received in a PSMP downlink transmission time (PSMP-DTT) is to be received in a later PSMP uplink transmission time (PSMP-UTT) when bit 6 of the frame control field is set to ‘0’.
5. The network device of claim 1 , wherein the frame is a data frame.
6. The network device of claim 1 , wherein refraining from transmitting the trigger-based immediate acknowledgement frame comprises:
waiting for a Block ACK Request frame for the frame; and
transmitting an acknowledgement frame for the frame to the AP in response to receiving the Block ACK Request frame.
7. The network device of claim 1 , wherein transmitting the trigger-based immediate acknowledgement frame comprises:
transmitting the trigger-based immediate acknowledgement frame a short inter frame space (SIFS) after receiving the DL MU PPDU.
8. The network device of claim 1 , wherein the trigger information includes information regarding an allocation of transmission resources for the UL MU transmission, and
wherein transmitting the trigger-based immediate acknowledgement frame comprises:
transmitting the trigger-based immediate acknowledgement frame by using a transmission resource allocated to the STA.
9. A method implemented by a station (STA) in a Wireless Local Area Network (WLAN) to acknowledge a downlink (DL) multi-user (MU) physical layer (PHY) Protocol Data Unit (PPDU) transmitted by an access point (AP), the method comprising:
receiving the DL MU PPDU;
decoding a frame from the DL MU PPDU;
determining whether an ACK Policy field of the frame is set to a binary value of ‘01’, wherein the binary value of ‘01’ indicates to the STA to provide a trigger-based immediate acknowledgement;
determining whether a trigger information for an uplink (UL) MU transmission has been obtained from the DL MU PPDU;
responsive to the determination that the ACK Policy field of the frame is set to the binary value of ‘01’ and a determination that the trigger information has been obtained from the DL MU PPDU, transmitting a trigger-based immediate acknowledgement frame to the AP, according to the trigger information; and
responsive to the determination that the ACK Policy field of the frame is set to the binary value of ‘01’ and a determination that the trigger information has not been obtained from the DL MU PPDU, refraining from transmitting the trigger-based immediate acknowledgement frame to the AP.
10. The method of claim 9 , wherein the binary value of ‘01’ is a reserved value for acknowledgement in a Power Save Multi-Poll (PSMP) context.
11. The method of claim 10 , wherein the ACK Policy field set to the binary value of ‘01’ in the PSMP context indicates to the STA that a response frame to a received frame is allowed but is neither an acknowledgement frame nor any data frame of subtype Contention Free-Acknowledgement (+CF-Ack) when bit 6 of a frame control field is set to ‘1’.
12. The method of claim 11 , wherein the ACK Policy field set to the binary value of ‘01’ in the PSMP context indicates to the STA that an acknowledgment for a frame received in a PSMP downlink transmission time (PSMP-DTT) is to be received in a later PSMP uplink transmission time (PSMP-UTT) when bit 6 of the frame control field is set to ‘0’.
13. The method of claim 9 , wherein the frame is a data frame.
14. The method of claim 9 , wherein refraining from transmitting the trigger-based immediate acknowledgement frame comprises:
waiting for a Block ACK Request frame for the frame; and
transmitting an acknowledgement frame for the frame to the AP in response to receiving the Block ACK Request frame.
15. The method of claim 9 , wherein transmitting the trigger-based immediate acknowledgement frame comprises:
transmitting the trigger-based immediate acknowledgement frame a short inter frame space (SIFS) after receiving the DL MU PPDU.
16. The method of claim 9 , wherein the trigger information includes information regarding an allocation of transmission resources for the UL MU transmission, and
wherein transmitting the trigger-based immediate acknowledgement frame comprises:
transmitting the trigger-based immediate acknowledgement frame by using a transmission resource allocated to the STA.