Method and apparatus for multi-user concurrent random access for wireless local area networks (WLANS)

1. A station (STA) comprising:

a transceiver; and

a processor,

the transceiver and the processor being configured to detect a trigger frame for an uplink (UL) multi-user (MU) transmission, the trigger frame including a user information field that includes an allocation of one or more random access resource units (RUs) and a common information field that includes information to seta high efficiency (HE) SIGNAL-A1 (HE-SIG-A1) field in the UL MU transmission, information to set an HE-SIG-A2 field in the UL MU transmission, and information indicating a number of HE-LTF symbols in an HE-LTF field in the UL MU transmission,

the transceiver and the processor being further configured to generate an HE trigger-based (TB) physical layer (PHY) protocol data unit (PPDU) and set an HE-SIG-A field and an HE-LTF field in the HE TB PPDU using the information in the trigger frame, and

the transceiver and the processor being further configured, on a condition that the STA has a pending frame to transmit to an access point (AP), to select one of the one or more random access RUs allocated in the trigger frame and transmit the HE TB PPDU, using the selected one of the one or more random access RUs, a short inter-frame space (SIFS) after the trigger frame.

2. The STA of claim 1 , wherein:

the user information field further includes an allocation of one or more dedicated RUs,

each dedicated RU is associated with an association identifier (AID) of a particular STA, and

each of the one or more random access RUs is associated with an AID reserved for random access.

3. The STA of claim 1 , wherein the trigger frame is aggregated with an acknowledgement (ACK) for at least one HE TB PPDU of a previous UL MU transmission.

4. The STA of claim 1 , wherein the processor and the transceiver are further configured to receive another trigger frame for a UL MU transmission, the other trigger frame being aggregated with an acknowledgement (ACK) for the HE TB PPDU.

5. The STA of claim 1 , wherein the trigger frame includes a field that includes a poll for a traffic buffer status of a WTRU.

6. The STA of claim 1 , wherein the allocation of the random access RUs is for an integer number, M, of RUs, and the processor and the transmitter are configured to select the one of the random access RUs allocated in the trigger frame by:

generating a random backoff counter value, R,

on a condition that R>M, holding the HE TB PPDU and decrementing R to R=R−M and using the decremented value of R to compete for a next MU random access opportunity, and

on a condition that R is less than or equal to zero, transmitting the HE TB PPDU.

7. The STA of claim 1 , further comprising an antenna communicatively coupled to the processor and the transceiver.

8. A method, implemented in a station (STA), the method comprising:

detecting a trigger frame for an uplink (UL) multi-user (MU) transmission, the trigger frame including a user information field that includes an allocation of one or more random access resource units (RUs) and a common information field that includes information to set a high efficiency (HE) SIGNAL-A1 (HE-SIG-A1) field in the UL MU transmission, information to set an HE-SIG-A2 field in the UL MU transmission, and information indicating a number of HE-LTF symbols in an HE-LTF field in the UL MU transmission;

generating an HE trigger-based (TB) physical layer (PHY) protocol data unit (PPDU);

setting an HE-SIG-A field and an HE-LTF field in the HE TB PPDU using the information in the trigger frame; and

on a condition that the STA has a pending frame to transmit to an access point (AP):

selecting one of the one or more random access RUs allocated in the trigger frame, and

transmitting the HE TB PPDU using the selected one of the one or more random access RUs a short inter-frame space (SIFS) after the trigger frame.

9. The method of claim 8 , wherein:

the user information field further includes an allocation of one or more dedicated RUs,

each dedicated RU is associated with an association identifier (AID) of a particular STA, and

each of the one or more random access RUs is associated with an AID reserved for random access.

10. The method of claim 8 , wherein the trigger frame is aggregated with an acknowledgement (ACK) for at least one HE TB PPDU of a previous UL MU transmission.

11. The method of claim 8 , further comprising receiving another trigger frame for a UL MU transmission, the other trigger frame being aggregated with an acknowledgement (ACK) for the HE TB PPDU.

12. The method of claim 8 , wherein the trigger frame includes a field that includes a poll for a traffic buffer status of a WTRU.

13. The method of claim 8 , wherein the assignment of random access RUs is for an integer number, M, of RUs, and the selecting the one of the random access RUs allocated in the trigger frame comprises:

generating a random backoff counter value, R,

on a condition that R>M, holding the HE TB PPDU and decrementing R to R=R−M and using the decremented value of R to compete for a next MU random access opportunity, and

on a condition that R is less than or equal to zero, transmitting the HE TB PPDU.

14. An access point (AP) comprising:

a transceiver; and

a processor,

the transceiver and the processor configured to generate and send a trigger frame, to two or more stations (STAs), for an uplink (UL) multi-user (MU) transmission, the trigger frame including a user information field that includes an allocation of one or more random access resource units (RUs) and a common information field that includes information to seta high efficiency (HE) SIGNAL-A1 (HE-SIG-A1) field in the UL MU transmission, information to set an HE-SIG-A2 field in the UL MU transmission, and information indicating a number of HE-LTF symbols in an HE-LTF field in the UL MU transmission,

the transceiver and the processor further configured to receive at least two HE trigger-based (TB) physical layer (PHY) protocol data units (PPDUs) from at least two of the STAs in a respective one of the RUs, each of the at least two HE TB PPDUs having at least portions of HE-SIG-A1, HE-SIG-A2 and HE-LTF fields that are identical based on the information in the trigger frame.

15. The AP of claim 14 , wherein:

the user information field further includes an allocation of one or more dedicated RUs,

each dedicated RU is associated with an association identifier (AID) of a particular STA, and

each of the one or more random access RUs is associated with an AID reserved for random access.

16. The AP of claim 14 , wherein the transceiver and the processor are further configured to aggregate the trigger frame with an acknowledgement (ACK) for at least one HE TB PPDU of a previous UL MU transmission.

17. The AP of claim 14 , wherein the processor and the transceiver are further configured to:

generate another trigger frame,

aggregate the other trigger frame with an acknowledgement for the at least two HE TB PPDUs, and

transmit the trigger frame to the two or more STAs.

18. The AP of claim 17 , wherein the processor and the transceiver are further configured to generate and transmit the other trigger frame after a last trigger frame in a cascading sequence of trigger frames.

19. The AP of claim 14 , wherein the trigger frame includes a field that includes a poll for a traffic buffer status of a WTRU.