Embodiments described herein methods and systems for channel correlation based user detection in an uplink multiuser transmission of a multiple-input multiple-output (MIMIO) network. In some embodiments, the channel correlation based user detection may be used in 802.11 UL MUMIMO systems. For example, an access point may detect whether a client station responds to a trigger frame and then adjust a channel matrix accordingly to reflect whether the client station is responsive. The access point may then decode received data signals based on the adjusted channel matrix that reflects whether a client station has transmitted.