The invention relates to a method, in an access point of a wireless local area network, of scheduling a radio resource, wherein at least one categorization rule is set in the wireless local area network, and at least one access group is set for a plurality of non-access-point stations served by the access point according to each of the at least one categorization rule, the method comprising the steps of: sending at least one categorization message to at least one of the plurality of stations, each categorization message comprising information about one of all the access groups which are set in the wireless local area network according to the at least one categorization rule; and sending a clear-to-send frame to the plurality of stations to indicate a radio resource allocated to an access group to be protected among all the access groups. The invention can distinctly resolve the contention for radio resource between the stations, effectively limit the number of concurrently contending stations and provide flexibility in access control of an access group.