A Study on Spectrum Sharing for Heterogeneous Networks Using Full 3D Area Model

In this paper, we propose a system level simulation method based on the full 3-dimensional area model, for heterogeneous networks wherein an Urban Macrocellular System (UMa) and Indoor Hotspot Systems (InH) share the same frequency band. To enable more realistic performance evaluations with moderate computational complexity, our method selects statistical propagation models appropriate to each pair of transmitter and receiver. It utilizes information of the obstacles on the direct path and site information such as indoor/outdoor, floor, building and city block. We evaluate the SINR distributions created when an UMa and InHs operate under exclusive-usage and spectrum-sharing conditions. The results are compared to the output of a conventional method based on the 2-dimensional area model, and a large difference between them is revealed. The results imply that the 2D model overestimates interference, while penetration losses from walls and floors are appropriately evaluated in the proposed 3D model. We also show the SINR distributions at receivers as degraded by spectrum sharing and the throughputs achieved by UMa and InHs in the exclusive-usage case and the spectrum sharing case.