A Genetic Algorithm for Network Expanded Problem in Wireless ATM Network

Abstract

In this paper, we investigate the network expanded prob- lem which optimally assigns new adding and splitting cells in PCS (Personal Communication Service) network to switches in an ATM (Asynchronous Transfer Mode) network. Moreover, the locations of all cells in PCS net- work are xed and known, but new switches should be installed to ATM network and the topology of the back- bone network may be changed. Given some potential sites of new switches, the problem is to determine how many switches will be added to the backbone network, the locations of new switches, the topology of the new backbone network, and the assignments of new adding and splitting cells in the PCS to switches on the new ATM network in an optimum manner. We would like to do the expansion in as attempt to minimize the to- tal communication cost under budget and capacity con- straints. This problem is modeled as a complex integer programming problem, and nding an optimal solution to this problem is NP-hard. A genetic algorithm is pro- posed to solve this problem. The genetic algorithm con- sists of three phases, Switch Location Selection Phase, Switch Connection Decision Phase, and Cell Assignment Decision Phase. First, in the Switch Location Selec- tion Phase, the number of new switches and the loca- tions of the new switches are determined. Then, Switch Connection Phase is used to construct the topology of the expanded backbone network. Final, Cell Assignment Phase is used to assign cells to switches on the expanded network. Experimental results indicate that the three- phase genetic algorithm has good performances.