Designing cellular networks using a parallel hybrid metaheuristic on the computational grid

6 7 Abstract 8 Cellular network design is a major issue in mobile telecommunication systems. In this paper, a model of the problem in its full prac-9 tical complexity, based on multiobjective constrained combinatorial optimization, has been investigated. We adopted the Pareto 10 approach at resolution in order to compute a set of diversified non-dominated networks, thus removing the need for the designer to rank 11 or weight objectives a priori. We designed and implemented a ''ready-to-use'' platform for radio network optimization that is flexible 12 regarding both the modeling of the problem (adding, removing, updating new antagonist objectives and constraints) and the solution 13 methods. It extends the ''white-box'' ParadisEO framework for metaheuristics applied to the resolution of mono/multi-objective Com-14 binatorial Optimization Problems requiring both the use of advanced optimization methods and the exploitation of large-scale parallel 15 and distributed environments. Specific coding scheme and genetic and neighborhood operators have been designed and embedded. On 16 the other side, we make use of many generic features related to advanced intensification and diversification search techniques, hybrid-17 ization of metaheuristics and grid computing for the distribution of the computations. They aim at improving the quality of networks 18 and robustness, to speed-up the search and obtain results in a tractable time, hence efficiently solving large instances of the problem. 19 Using three realistic benchmarks, the computed networks and speed-ups on different parallel and/or distributed architectures show 20 the efficiency and the scalability of hierarchical models of hybridization and parallelization used in conjunction. 21 Ó 2006 Published by Elsevier B.V. 22 23 1. Introduction 24 The design of large cellular networks is a complex task 25 with a great impact on the quality of service and the cost 26 of the network. Engineering of mobile telecommunication 27 networks involves two major problems: the design of the 28 network and the frequency planning. The design consists 29 in positioning base stations (BS) on potential sites, in order 30 to fulfill some objectives and constraints [20]. The frequen-31 cy planning sets up frequencies used by BS with criteria of 32 reusing. In this paper, we address the first problem. Net-33 work design is an NP-hard combinatorial optimization 34 problem [21]. The BS positioning problem deals with find-35 ing a set of sites for antennas from a set of pre-defined can-36 didate sites, determining the type and the number of 37 antennas, and setting up …