Cost optimization of integrated network planning based on adaptive sectorization in hybrid F/CDMA telecommunications system via Lagrangean relaxation

In this paper, we investigate the integrated network planning for telecommunications system, which considers adaptive sectorization and a hybrid F/CDMA scheme jointly under quality of service (QoS) constraints. The problem is formulated as a combinatorial optimization formulation in terms of minimizing the cost. We also investigate the viability of using Lagrangean relaxation (LR) to solve the problem. With regard to the computational results, the cost of considering network error states in the planning stage is 45% more than that of non-error. The proposed LR approach outperforms a simple algorithm with a cost improvement of 60%. In addition, the link constraint is more important to the total cost than the node constraint. Given a link constraint, the cost is affected more significantly by a decreasing threshold than by an increasing threshold. The proposed model is not only a valuable reference for network planning in a new field (e.g., a desert scenario), but also fits the planning requirements when some equipment pre-exists (an embedded scenario). We assign constant values to several decision variables, so the model is adaptable to various scenarios. 2011 Elsevier Ltd. All rights reserved.