according to an aspect of an embodiment , a base station includes a first interface , a second interface , a third interface , and an allocator . the first interface communicates with a plurality of terminals via a licensed radio spectrum . the second interface communicates with the plurality of terminals via an unlicensed radio spectrum . the third interface receives from a central controller a licensed radio spectrum assignment including a set of assigned physical resource blocks associated with the licensed radio spectrum . the allocator allocates unlicensed radio spectrum resources and the physical resource blocks among the plurality of terminals .