Impact of network densification, site placement and antenna downtilt on the capacity performance in microcellular networks.

In this paper we evaluate the capacity performance of a microcellular network deployment in a dense urban Manhattan grid environment. Different microcellular layouts with varying cell densities per sq. km are investigated, while considering the outdoor and as well as indoor propagation environments. Three main capacity enhancing techniques, network densification, site placement and antenna downtilt are utilized and their effect on cell spectral efficiency and area spectral efficiency is assessed. As a result of densification, the network capacity for outdoor environment can be improved since the area spectral efficiency increases. However, due to significant reduction of cell spectral efficiency, the area spectral efficiency starts to saturate for indoor environments. The results also indicate that careful site placement can enhance the capacity performance in both outdoor and indoor environments. Moreover, antenna downtilt configuration is shown to improve the area capacity in the outdoor environment with minor improvement for indoor environments. The results hence indicate that microcellular network densification suffers from capacity inefficiency even when performance techniques like antenna downtilt is utilized. This calls for alternative methods to deploy networks, e.g., indoor networks.