Apparatus, computer readable medium, and methods for initiating uplink multi-user medium access in high-efficiency wireless local-area networks (WLANs) are disclosed. A station is disclosed comprising circuitry configured to generate a trigger frame comprising one or more resource allocations. Each of the resource allocations may include an indication of whether the resource allocation is an orthogonal frequency division multiple access (OFDMA) resource allocation or a multiple-user multiple-input multiple-output (MU-MIMO) resource allocation. An identity either of an OFDMA group or an MU-MIMO group may be included. Each resource allocation may include an indication of a bandwidth for the OFDMA resource allocation or a bandwidth for the MU-MIMO resource allocation. Each OFDMA resource allocation may include one or more indications of an address of one or more HE stations and one or more indications of an OFDMA sub-channel resource allocation for the corresponding HE station.