An AP receives, from one or more STAs, an uplink orthogonal frequency division multiple access based block acknowledgement response in an 802.11 based wireless network. The AP transmits the downlink allocation for the downlink frame to the plurality of mobile devices, wherein the order of the plurality of mobile devices in the downlink allocation indicates respective uplink resource assignments. The STA receives a downlink frame with an allocation comprising the listing of a plurality of mobile devices for which data is transmitted in the downlink frame. The STA identifies an uplink resource allocation as a function of a location of a first mobile device within the listing of the plurality of mobile devices. The STA then transmits an acknowledgment on the uplink resource allocation corresponding to the location of a first mobile device within the listing of the plurality of mobile devices.