Performance Analysis of Micro Site with Tilted Antenna in a Realistic High Rise Building Scenario

Outdoor Micro cell has been considered as a cost efficient way to increase in-building coverage and capacity. Micro cell configured with up-tilting antenna potentially improve the high floor coverage in high rise buildings. In this paper, the network performance of micro site is studied using a realistic TD-LTE network located in city center of Beijing with many high rise buildings. Micro User Equipment (UE)´s location and offloading ratio impacted by antenna up-tilting is evaluated through system level simulation. In the simulation, we assume micro site is configured with three directional antennas, and deployed using dedicated carrier. To model accurately the user distribution and radio propagation, the three-dimensional (3D) city map is employed. A 3D ray-tracing tool is applied to estimate the propagation of the studied area. A semi-empirical building penetration extension is proposed to derive indoor predictions for each floor based on outdoor predictions at ground-level, combining with a height gain model. Simulation results indicate that micro antenna up- tilting will diminish the coverage area of the micro sites, but give a significant improvement on the offloading capability for high floor UEs.