11. An access point (AP) in a wireless, the wireless network comprising the AP and a plurality of wireless stations associated with the AP, the AP comprising:a transmitting/receiving unit; and
at least one processing unit communicatively coupled to the transmitting/receiving unit, the at least one processing unit configured to:
define one or more criteria for categorizing the plurality of wireless stations in the wireless network into a plurality of categories, the plurality of categories comprising at least a first category and a second category, the one or more criteria comprising at least a link-quality-parameter;
determine each of the plurality of wireless stations as belonging to one of the plurality of the categories, wherein more than one of the plurality of wireless stations are determined to belong to the first category and at least one of the plurality of wireless stations is determined to belong to the second category;
notify the wireless stations of one or more first scheduled time periods and one or more second scheduled time periods;
during the one or more first scheduled time periods, transmit first user data to a first wireless station in the first category, and transmit a first collision avoidance control message related to the first user data using a first signaling transmission power; and
during the one or more second scheduled time periods, transmit second user data to a first wireless station in the second category, and transmit a second collision avoidance control message related to the second user data using a second signaling transmission power, the second signaling transmission power being different from the first signaling transmission power.