Modelos teóricos e algoritmos para a otimização da alocação de canais em redes móveis sem fio

Abstract

The channel allocation problem is addressed, where, as a wireless mobile network with transmission antennas distributed in the region of interest and one or more given track limited frequency discretized broadcast channels, is to promote allocation of such channels by the antennas in such a way to meet the demand for calls optimizing the use of resources, which in this case prioritized to optimize the use of channels allocated in an optimization problem Min-Max distribution channel - the Span -, where the highest allocated channel must be as small as possible. This problem has a increasingly important given the large demand growth and limiting technological resources of communication involved. The approach to the problem is Optimization Combinatorics and related fields. Therefore, a literature study is presented on the topic, focusing on mobile phones and networks based on cognitive radio networks. The From this, it is proposed new theoretical model for the problem representation using special stains on graphs, task scheduling on parallel machines resource constraints and geometry distances with constraint programming, and possible to identify specific characteristics of some application scenarios of the problem general. Based on these models, the developed algorithms are presented and implemented, and approximate methods based on local search with emphasis on meta-heuristic simulated annealing, and exact methods, involving branch-and-cut with IBM / ILOG CPLEX tool and, finally, hybrid methods, prune-branch-and-bound. The computational experiments are presented with a comparative analysis of performance, either using classical literature instances, as set Philadelphia and its variants as well as artificial instances proposals to cover variants discussed, as well as larger involving network 70 to to 150 stations. The results validate the proposed theoretical models and algorithms developed and implemented, since, equal or better results to the literature were obtained with several great solutions proven, beyond theoretical discussion and variants proposals believed to strengthen the understanding of the problem and the related literature