A method of allocating resources in a first wireless system, wherein the first wireless system shares a frequency spectrum with a second wireless system, is described. The method comprises detecting a level of interference to the second wireless system caused by the first wireless system on a first frequency within the spectrum; determining if transmission on the first frequency should be restricted based on the level of interference; and restricting transmissions in the first system on the first frequency if it was determined that transmission on the first frequency should be restricted while allowing normal use of the remaining portions of the frequency spectrum to continue in the first system. A system for allocating resources in a first wireless system, wherein the first wireless system shares a frequency spectrum with a second wireless system, is also described.