Femtocell Base Station Deployment in Commercial Buildings: A Global Optimization Approach

While the deployment of femtocell in residential buildings has firmly positioned it as a major performance leap in wireless communications, its deployment in commercial buildings remains under-explored. In commercial building environments, the femtocell base station (FBS) placement planning is particularly challenging due to the impact of the building size, layout, structure, and wall/floor separation. In this paper, we study the problem of jointly optimizing FBS placement and power control in commercial building environments to prolong the battery life for mobile handsets. We first propose a mathematical model that captures the unique building features. Based on this model, we employ a set of novel transformation strategies to formulate the FBS placement problem as a mixed-integer convex program (MICP). Accordingly, we propose an effective global optimization algorithm based on using the convex relaxation of the formulated MICP within a branch-and-bound framework. This approach guarantees finding a global optimal solution. To demonstrate the efficacy of our algorithm, we conduct extensive numerical studies. Our proposed model and optimization approach offer useful insights into femtocell deployments in commercial buildings.