In accordance with an embodiment, a method is provided in which a first wireless access point sends a downlink multi-user multiple-input multiple-output (MIMO) transmission to a plurality of client devices. The downlink multi-user MIMO transmission is configured to solicit acknowledgments from two or more of the plurality of client devices. The acknowledgments are received at a plurality of antennas of the first wireless access point from the two or more of the plurality of client devices. Uplink multi-user MIMO processing of the acknowledgments is performed from the two or more of the plurality of client devices to recover the acknowledgments respectively from each of the two or more of the plurality of client devices.