The present disclosure provides various aspects related to techniques for generating trigger frames, at an access point (AP), that reduce the overhead associated with triggering an uplink transmission from the wireless station (STA). Features of the present disclosure achieve this by, for example, utilizing a single per-user information field of the trigger to signal a plurality of random access resource units that may be allocated to the one or more STAs in the network. Such a technique is an improvement over the conventional system that require each random access resource unit to be signaled separately in a separate per-user information field (thus increasing the overhead). Additionally, aspects of the present disclosure allow the AP to effectively signal to the STA whether the one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation.