Acknowledgements in response to received frames

1. A station (STA) comprising:

a receiver configured to receive a request to send (RTS) frame from an access point (AP), the receiver configured to receive a duration field indicating a duration of a data unit and a duration of a block acknowledgement (block-ACK) frame, wherein the duration of the block-ACK frame is derived from a parameter pre-negotiated between the STA and the AP;

a transmitter configured to transmit a clear to send (CTS) frame;

the receiver configured to receive a control frame that indicates that the control frame is for a group of STAs and further indicates that the control frame is a block-ACK control frame;

the transmitter configured to transmit the data unit to the AP; and

the receiver configured to receive the block-ACK frame, from the AP, after the control frame, wherein the block-ACK frame is addressed to a broadcast address and includes a plurality of subfields, each one of the plurality of subfields comprising an association identifier (AID) and a traffic identifier (TID).

2. The STA of claim 1 , wherein the block-ACK frame includes AID bits corresponding to an AID of another STA, a TID corresponding to other data, a starting sequence number and a bitmap.

3. The STA of claim 1 , wherein reception of the block-ACK frame follows a delay period from transmission of the data unit.

4. The STA of claim 1 , wherein the RTS frame includes the duration field indicating the duration of the data unit and the duration of the block-ACK frame.

5. The STA of claim 1 , wherein the duration field indicates a duration of the control frame.

6. The STA of claim 1 , wherein the parameter pre-negotiated between the STA and the AP is negotiated prior to receipt of the RTS frame.

7. A method for operation by an access point (AP), the method comprising:

transmitting a request to send (RTS) frame and transmitting duration information indicating a duration of an acknowledgement (ACK) frame, wherein the duration of the ACK frame is derived from a pre-negotiated parameter;

receiving a clear to send (CTS) frame;

transmitting a control frame that indicates that the control frame is for a group of STAs and further indicates that the control frame is a block-ACK control frame;

receiving a first data unit from a first STA, the first data unit comprising first data;

receiving a second data unit from a second STA, the second data unit comprising second data; and

transmitting the ACK frame to the first STA and the second STA after transmitting the control frame, wherein the ACK frame is addressed to a broadcast address and includes a field which indicates whether the ACK frame is a multiple traffic identifier (multi-TID) block ACK frame format or another ACK frame format.

8. The method of claim 7 , wherein the ACK frame includes an indication of whether the first data and the second data was correctly received by the AP.

9. The method of claim 7 , wherein the ACK frame includes AID bits corresponding to an AID of the first STA, a TID corresponding to the first data, a first starting sequence number and a first ACK bitmap.

10. The method of claim 9 , wherein the ACK frame further includes AID bits corresponding to an AID of the second STA, a TID corresponding to the second data, a second starting sequence number and a second ACK bitmap.

11. The method of claim 10 , wherein the TID corresponding to the first data is different than the TID corresponding to the second data.

12. The method of claim 9 , wherein each bit of the first ACK bitmap indicates an ACK or NACK for a frame associated with the TID.

13. The method of claim 7 , wherein the ACK frame is a block ACK frame type; and

wherein the control frame is a different frame than the ACK frame.

14. An access point (AP) comprising:

a transmitter configured to transmit a request to send (RTS) frame and duration information indicating a duration of an acknowledgement (ACK) frame, wherein the duration of the ACK frame is derived from a pre-negotiated parameter;

a receiver configured to receive a clear to send (CTS) frame;

the transmitter configured to transmit a control frame that indicates that the control frame is for a group of STAs and further indicates that the control frame is a block acknowledgement (block-ACK) control frame;

the receiver configured to receive a first data unit from a first STA, the first data unit comprising first data;

the receiver configured to receive a second data unit from a second STA, the second data unit comprising second data; and

the transmitter configured to transmit the ACK frame to the first STA and the second STA, after the control frame, wherein the ACK frame is addressed to a broadcast address and includes a field which indicates whether the ACK frame is a multiple traffic identifier (multi-TID) block ACK frame format or another ACK frame format.

15. The AP of claim 14 , wherein the ACK frame includes an indication of whether the first data and the second data was correctly received by the AP.

16. The AP of claim 14 , wherein the ACK frame includes AID bits corresponding to an AID of the first STA, a TID corresponding to the first data, a first starting sequence number and a first ACK bitmap.

17. The AP of claim 16 , wherein the ACK frame further includes AID bits corresponding to an AID of the second STA, a TID corresponding to the second data, a second starting sequence number and a second ACK bitmap.

18. The AP of claim 17 , wherein the TID corresponding to the first data is different than the TID corresponding to the second data.

19. The AP of claim 16 , wherein each bit of the first ACK bitmap indicates an ACK or NACK for a frame associated with the TID.

20. The AP of claim 14 , wherein the ACK frame is a block ACK frame type; and

wherein the control frame is a different frame than the ACK frame.