A method for scheduling a random access trigger frame (RA TF) in a wireless LAN includes determining whether a scheduled access (SA) TF is scheduled during a beacon interval (BI) beginning with a next beacon; determining whether one of, a first weighted average of a sum of (i) a number of clients whose respective buffer status reports (BSRs) have been successfully received (NSUCC) and (ii) a number of clients whose respective BSRs collided with one another (NCOL) is greater than a first threshold, or a second weighted average of an active number of UL OFDMA enabled HE users sending SU uplink traffic (NSU) is greater than the first threshold; when either weighted average is greater than the first threshold, allocating a predetermined number of RA RUs along with at least one SA RU in a buffer status report poll (BSRP) TF and scheduling the BSRP TF for transmission.