Systems, methods, and instrumentalities are disclosed for range extension, basic service set (BSS) color labeling, and multi-user (MU) fragmentation and control in WLANs. A range extension notification/enablement scheme, a clear channel assessment (CCA), a headroom indication, and/or power scaling may be provided for a range extension mode. BSS color may be provided for multiple-BSSs under an access point (AP). Uplink (UL) transmission may be provided with different fragmentation capabilities. A high-efficiency (HE) trigger-based UL NDP physical layer convergence protocol (PLCP) protocol data unit (PPDU) frame may be provided. A station (STA) may receive a trigger frame comprising a null data packet (NDP) indication and a trigger type. The STA may determine that the STA is an intended recipient of the trigger frame. The STA may prepare an NDP PPDU for a control frame and/or a management frame based on the trigger type.