Embodiments of a user station (STA), access point (AP), and method for random access contention in a wireless network are generally described herein. The STA may receive, from the AP, a beacon frame for a beacon interval. The STA may further receive a first random access Trigger Frame (TF) that indicates a first allocation of channel resources for random access contention by STAs during a first uplink transmission period of the beacon interval. The beacon frame may include a transmission timing for the first random access TF and a first TF cascade type for the first random access TF. The first TF cascade type may indicate whether a next TF is a random access TF or a scheduled access TF.