Research And Application On A Large Scale Fading Model Based On 3D Ray-tracing

In wireless communications,the received signal power is modeled as a combination of path loss,shadow fading and small-scale fading.The accuracy of these three aspects has a vital influence on the network planning and deployment.When calculating the PathLoss,Ray Tracing considers the reflected,diffracted,and scattered copies of the transmitted signals,which makes it more accurate when predictingthe Path Loss of different specific scenarios than empirical models.Based on the practical network,this paper focuses on the impact of the distribution of UEs' height when calculating the Path Loss.And then proposed the HeightGain(h)which indicates the Path Loss(or Link Loss)difference between UE at height of h and UE at reference height h0.The simulation results show that there is one turn point appears at BS height,before which the curve slope is-0.2dB/m.When above BS height,the height gain goes up slowly.,and the 2nd turn point is around 60m height.Since more factors are involved,i.e.antenna gain,the curves of directional-antenna case is more complex and have larger dynamic range than that of omni-antenna one.The impact of HeightGain on system performance is also given in this paper.The comparisonbetween the scenarios that considering HeightGain and the conventional ones,respectively on the indoor average SINR,indoor outage rateandindoor DL average throughput,shows distinct differences,therefore the HeightGain is meaningful on network planning and deployment.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 was studied using a realistic TD-LTE network located in city center of Beijing with many high rise buildings.Micro UE's location and offloading ratio impacted by antenna up-tilting was 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 uptilting will diminish the coverage area of the micro sites,but give a significant improvement on the offloading capability for high floor UEs.