Frequency Band Assignment Method for a Wireless Communication System and Device Using the Same

A frequency band assignment method for a wireless communication system is disclosed. The wireless communication system includes a plurality of base stations. The plurality of base stations has overlapped radio ranges and forms a plurality of independent overlapping areas. The method includes steps of modeling the plurality of base stations as a plurality of variable nodes in a factor graph, modeling the plurality of independent overlapping areas as a plurality of constraint nodes in the factor graph, and using the factor graph to perform frequency assignment for the plurality of base stations. Each variable node is defined as a frequency band to be assigned to the modeled base station. Each constraint node is defined as that the frequency bands assigned to the base stations forming the modeled overlapping area cannot be equivalent.