1. A method for performing a multi-user uplink transmission, the method comprising:assessing, by an access point, a wireless channel using clear channel assessment parameters;
determining spatial reuse information based on the assessment of the wireless channel;
generating a trigger frame; and
transmitting the trigger frame,
wherein the trigger frame includes resource allocation information for a first wireless station and a second wireless station to participate in the multi-user uplink transmission to the access point, and
wherein the trigger frame further includes the spatial reuse information in a payload of the trigger frame, the spatial reuse information to be used by the first wireless station and the second wireless station for respectively setting a spatial reuse field in the multi-user uplink transmission.