At a given point in time, multiple STAs, in the WLAN, may wish to send data. In some configurations, rather than scheduling medium access for STAs 106 in different respective UL time intervals, the AP 104 may schedule medium access for STAs 106 to support UL MU transmission techniques, according to which multiple STAs 106 may transmit UL MU PPDUs to the AP 104 simultaneously during a given UL time interval. For example, by using UL MU OFDMA techniques during a given UL time interval, multiple STAs 106 may transmit UL MU PPDUs to the AP 104 via different respective OFDMA Resource Units (RUs) allocated by the AP 104. In another example, by using UL MU-MIMO techniques during a given UL time interval, multiple STAs 106 may transmit UL MU PPDUs to the AP 104 via different respective spatial streams allocated by the AP 104.

To manage access, the AP 104 may transmit a master-sync transmission, which may be a Trigger Frame (TF) or a control and schedule transmission, at the beginning of the control period. The AP 104 may transmit a time duration of the TXOP and sub-channel information. During the control period, STAs 106 may communicate with the AP 104 in accordance with a non-contention based multiple access technique, such as OFDMA or MU-MIMO. This technique is unlike conventional WLAN communications in which devices communicate in accordance with a contention-based communication technique, rather than a multiple access technique. During the control period, the AP 104 may communicate with stations 106 using one or more control frames, and the STAs 106 may operate on a sub-channel smaller than the operating range of the AP 104.