Methods, apparatuses and systems for supporting multi-user transmissions in a wireless local area network (WLAN) system
Methods, devices and systems are provided for performing for multi-user (MU) transmission. A wireless transmit/receive unit (WTRU) may be configured to receive a frame, decode the received frame and determine whether the received frame is a null data packet (NDP) multi-user (MU) media access control (MAC) physical layer convergence protocol (PLCP) protocol data unit (PPDU) (NDP MU MAC PPDU) based on meeting an NDP condition. The NDP MU MAC PPDU may correspond to an MU transmission and may include a PLCP header which includes an NDP signal (SIG) field having MU control information. Based on the received frame meeting the NDP condition, the WTRU may be further configured to process the NDP SIG field, generate a response based on the NDP SIG field and the MU control information, and transmit the response.
1. A method for use in a station (STA), the method comprising:
receiving, from an access point (AP), a high-efficiency multi-user (HE MU) poll frame that includes an association identifier (AID) indicating a plurality of STAs scheduled for multi-user (MU) uplink transmission over one or more sub-channels; and
transmitting, to the AP, on a condition that the received AID corresponds to an AID that is associated with the STA, an Null Data Packet (NDP) Uplink Response (ULR) frame over a sub-channel selected, based on the received AID, from the one or more sub-channels, wherein the NDP ULR frame indicates that the STA has the uplink data to transmit in the traffic buffer.
2. The method of claim 1 , wherein the AID is a partial AID.
3. The method of claim 1 , wherein the sub-channel is distinguished from another sub-channel in which another NDP ULR frame is simultaneously transmitted to the AP from another STA.
4. The method of claim 3 , wherein the sub-channel and the another sub-channel are separated in frequency.
5. The method of claim 1 , wherein an interframe space between the NDP ULR frame and the HE MU poll frame is a short interframe space (SIFS).
6. A station (STA) comprising:
a processor;
a receiver; and
a transmitter,
the processor and the receiver configured to receive, from an access point (AP), a high-efficiency multi-user (HE MU) poll frame that includes an association identifier (AID) indicating a plurality of STAs scheduled for multi-user (MU) uplink transmission over one or more sub-channels; and
the processor and the transmitter configured to transmit, to the AP, on a condition that the received AID corresponds to an AID that is associated with the STA, an Null Data Packet (NDP) Uplink Response (ULR) frame over a sub-channel selected, based on the received AID, from the one or more sub-channels, wherein the NDP ULR frame indicates that the STA has the uplink data to transmit in the traffic buffer.
7. The STA of claim 6 , wherein the AID is a partial AID.
8. The STA of claim 6 , wherein the sub-channel is distinguished from another sub-channel in which another NDP ULR frame is simultaneously transmitted to the AP from another STA.
9. The STA of claim 8 , wherein the sub-channel and the another sub-channel are separated in frequency.
10. The STA of claim 6 , wherein an interframe space between the NDP ULR frame and the HE MU poll frame is a short interframe space (SIFS).