ACK policy for uplink and downlink MU PPDU
A network device is provided. The network device includes one or more memories and one or more processors coupled to the one or more memories. The one or more processors are configured receive a DL MU PPDU, decode a data frame including a media access control (MAC) header from the DL MU PPDU, determine whether an acknowledgement (ACK) policy indicated in the MAC header signals a trigger-based immediate acknowledgement policy, and determine whether a trigger indication for an uplink (UL) MU transmission has been obtained from a payload of a data frame. Responsive to the processor determines that the trigger indication has not been obtained, the processor is configured to not transmit an immediate acknowledgement to the access point. In response to the trigger indication has not been obtained but the station has obtained a transmission opportunity, the station returns an ACK/Block ACK frame in an unsolicited manner.
1. A network device to function as a station in a Wireless Local Area Network (WLAN), the station configured to acknowledge a downlink (DL) multi-user (MU) physical layer (PHY) Protocol Data Unit (PPDU) transmitted by an access point, comprising:
one or more memories; and
one or more processors coupled to the one or more memories, configured to:
receive the DL MU PPDU;
decode a data frame from the DL MU PPDU, the data frame comprising a media access control (MAC) header;
determine whether an acknowledgement (ACK) policy indicated in the MAC header signals a trigger-based immediate acknowledgement policy;
determine whether a trigger indication for an uplink (UL) MU transmission has been obtained from a payload of a data frame;
responsive to the processor determines that the ACK policy indication signals the trigger-based immediate acknowledgement policy and determines that the trigger indication has been obtained, the processor is configured to:
transmit a trigger-based immediate acknowledgement frame to the access point in an UL MU PPDU, based on the trigger indication; and
responsive to the processor determines that the ACK policy signals the trigger-based immediate acknowledgement policy and determines that the trigger indication has not been obtained, the processor is configured to:
not transmit an immediate acknowledgement to the access point, wherein in response to the trigger indication has not been obtained but the station has obtained a transmission opportunity, the station returns an ACK/Block ACK frame in an unsolicited manner.
2. The network device of claim 1 , wherein the trigger-based immediate acknowledgement is signaled by a ‘1’ in bit 6 of a Quality of Service (QoS) control field and a ‘0’ in bit 5 of the QoS control field, wherein the QoS control field is included within the MAC header.
3. The network device of claim 1 , wherein the processor is configured to not transmit an immediate acknowledgement is further signaled by a ‘1’ in bit 6 of a Frame Control field included within the MAC header.
4. The network device of claim 1 , wherein in response to the processor is configured to not transmit the trigger-based immediate acknowledgement frame and not transmit an ACK/Block ACK frame in an unsolicited manner, the processor is configured to:
wait for a Block ACK Request frame for the frame; and
transmit an acknowledgement frame for the frame to the access point in response to the processor receives the Block ACK Request frame.
5. The network device of claim 1 , wherein the processor is configured to transmit the trigger-based immediate acknowledgement frame comprises the processor is configured to:
transmit the trigger-based immediate acknowledgement frame a short inter-frame space (SIFS) after receiving the DL MU PPDU.
6. The network device of claim 1 , wherein the trigger information comprises information that indicates an allocation of transmission resources for the UL MU transmission, wherein the processor is configured to transmit the trigger-based immediate acknowledgement frame comprises the processor is configured to:
transmit the trigger-based immediate acknowledgement frame by using a transmission resource allocated to the station.
7. The network device of claim 1 , wherein the unsolicited ACK/Block ACK frame transmission is processed in a similar manner as a delayed Block ACK policy.
8. The network device of claim 1 , wherein a BAR field in the trigger-based immediate acknowledgement frame includes a frame control field, a duration/ID field, a receiver and transmitter address field, a block acknowledgement request control field, a per-user BlockAck request (BAR) field and a per-user subchannel assignment field.
9. The network device of claim 8 , wherein the BAR field comprises a number of users from which an immediate acknowledgement is requested and the per-user Block ACK Request field and the per-user subchannel assignment field is repeated for each user.
10. The network device of claim 1 , wherein in response to a Block ACK Request frame in a DL MU PPDU includes an indication that the station should provide an immediate acknowledgement in a single-user (SU) manner, the acknowledgement behavior of the station depends on whether the Block ACK Request frame is in a PSMP context or a UL OFDMA context.