In wireless LANs, different multi-user access methods such as TDMA, OFDMA and SDMA are available which can be used with or without channel knowledge at the transmitter and a single antenna (MISO) or multiple antennas (MIMO) at the receiver. A cross-layer scheduler is considered which can be configured with these different PHY methods as well as with knowledge about application requirements and channel conditions at the MAC layer. The scheduler computes priorities on the MAC layer that are handed over to the physical layer in order to keep quality-of-service constraints such as throughput and delay. In this paper, it is demonstrated that controlling the priorities by a QoS aware resource allocation method allows to meet the requirements by the applications under various channel conditions. MISO-SDMA has a relatively small performance penalty in comparison to MIMO-SDMA which gives the best result. For MIMO-TDMA and -OFDMA, channel knowledge at the PHY layer does not result in essential performance enhancement.