(A) study on the optimal channel assignment problem in the mobile system

Abstract

This thesis is concerned with the channel assignment for the design of cellular mobile communication systems. Our first model is an optimal channel assignment problem which minimize the weighted average blocking probability subject to only co-channel interference constraints. The problem is converted into al linear mixed integer problem. We apply a Lagrangean relaxation procedure to the mixed integer problem to obtain lower bounds and feasible solutions. Computational experiments show that our method found high-quality solutions with information about meaningful error ranges. In second model, we consider an optimal channel assignment problem which minimize the span of frequencies required subject to generalized constraints. For this problem, we suggeste a heuristic algorithm for the minimum span problem. And the computational experiment is performed with the algorithm and comparisons are made with the existing algorithms. The result show that our algorithm is superior over the existing algorithms in all the problems tested. We apply this algorithm successfully to the problem which minimize the weighted average blocking probability.