Abstract-Base station antenna downtilt is one of the most important parameters for optimizing a cellular network with tight frequency reuse. By downtilting, inter-site interference is reduced, which leads to an improved performance of the network. In this study we show that a simple geometrical-based extension to standard empirical path loss prediction models can give quite reasonable accuracy in predicting the signal strength from tilted base station antennas in small urban macro-cells. Our evaluation is based on measurements on several sectors in a 2.6 GHz Long Term Evolution (LTE) cellular network, with electrical antenna downtilt in the range from 0 to 10 degrees, as well as predictions based on ray-tracing and 3D building databases covering the measurement area. Although the calibrated ray-tracing predictions are highly accurate compared with the measured data, the combined LOS/NLOS COST-WI model with downtilt correction performs similarly for distances above a few hundred meters. Generally, predicting the effect of base station antenna tilt close to the base station is difficult due to multiple vertical sidelobes.
As for the second area of works, the work in REF proposes a geometrical-based extension to different traditional logdistance path loss models (Okumura-Hata, Walfisch-Ikegami) to take into account the antenna tilt during the prediction of the signal strength at a given distance from the base station.
A Geometrical-Based Vertical Gain Correction for Signal Strength Prediction of Downtilted Base Station Antennas in Urban Areas
2012 IEEE Vehicular Technology Conference (VTC Fall)
2012 IEEE Vehicular Technology Conference (VTC Fall)
Computer Science