A method and apparatus of signaling radio resource allocation in a wireless communication system comprises establishing a set of virtual resources; assigning one or more of the virtual resources to one or more mobile stations; transmitting a remapping bitmap to the mobile stations, wherein the remapping bitmap contains a resource availability bitmap and a virtual resource bitmap; and transmitting packets to the mobile stations or receiving packets from the mobile stations using the respective radio resources which are derived for the respective mobile stations from the remapping bitmap.