Algorithm design for femtocell base station placement in commercial building environments

Although femtocell deployments in residential buildings have been increasingly prevalent, femtocell deployment in commercial building environments remains in its infancy. One of the main challenges lies in the femtocell base stations (FBS) placement problem, which is complicated by the buildings´ size, layout, structure, and floor/wall separations. In this paper, we investigate a joint FBS placement and power control optimization problem in commercial buildings with the aim to prolong mobile handsets´ battery lives. We first construct a mathematical model that takes into account the unique floor attenuation factor (FAF) and FBS installation restrictions in building environments. Based on this model, we propose a novel two-step reformulation approach to convert the original mixed-integer nonconvex problem (MINCP) into a mixed-integer linear program (MILP), which enables the design of efficient global optimization algorithms. We then devise a global optimization algorithm by utilizing the MILP in a branch-and-bound framework. This approach guarantees finding a global optimal solution. We conduct extensive numerical studies to demonstrate the efficacy of the proposed algorithm. Our mathematical reformulation techniques and optimization algorithm offer useful theoretical insights and valuable tools for future commercial building femtocell deployments.