FIXED CHANNEL ASSIGNMENT IN CELLULAR RADIO NETWORKS USING A MODIFIED GENETIC ALGORITHM

With the limited frequency spectrum and an increasing demand for cellu lar communication services, the problem of channel assignment becomes increasingly important, However, finding a conflict-free channel assig nment with the minimum channel span is NP hard. Therefore, we formulat e the problem by assuming a given channel span. Our objective is to ob tain a conflict-free channel assignment among the cells, which satisfi es both the electromagnetic compatibility (EMC) constraints and traffi c demand requirements, We propose an approach based on a modified gene tic algorithm (GA), The approach consists of a genetic-fix algorithm t hat generates and manipulates individuals with fixed size (i.e., in bi nary representation, the number of ones is fixed) and a minimum-separa tion encoding scheme that eliminates redundant zeros in the solution r epresentation, Using these two strategies, the search space can be red uced substantially, Simulations on the first four benchmark problems s howed that this algorithm could achieve at least 80%, if not 100%, con vergence to solutions within reasonable time, In the fifth benchmark p roblem, our algorithm found better solutions with shorter channel span than any existing algorithms, Such significant results indicate that our approach is indeed a good method for solving the channel-assignmen t problem.