# Employing Ray-Tracing and Least-Squares Support Vector Machines for Localisation +
## 2 Experimental Setup and Methodology  
### Ray Tracing  
Ray-tracing software that was developed at the University of Bristol, is used in this study. It is based on a validated, realistic 3D ray-traced channel model as used in [9; 10]. The same ray-tracing model was used to generate most of the statistics that are now specified in the 3D extension of the 3 GPP/ITU channel model [11]. The ray tracing tool incorporates a real-world environmental database of the City of Bristol (UK), which is a 3D Laser Illuminated Detection & Ranging (LIDAR) database of the city. Figure 1 shows, as an example, a point-to-point BS-MS link with all the determined rays (multipath rays) between the BS and the MS.  
Ray-tracing is conducted at a carrier frequency of 3.51 GHz to match the carrier frequency used on the Bristol massive MIMO testbed [12]. The transmit power is set to 32 dBm and the receiver sensitivity is configured to be \(-120\) dBm. Isotropic antennas are used at both the BS and the MS at runtime. After that, any required transmit and/or receive antenna pattern and geometry are applied during  
Figure 1: Multipath rays for a BS-MS point-to-point link.  
post-processing, as a spatial-polarisation-phase convolution process. Table 1 shows the parameters that are produced for each ray.  
Hundreds of base station (BS) to mobile station (MS) links were simulated to generate 3D ray data for different areas of the greater city of Bristol. A 6 \(\times\) 6 BS grid that covers approximately 1 km\({}^{2}\), is placed on parts of the city. The BS to BS distance is approximately 300 m. The BS deployment is made very dense, mainly to make sure that every position within the area of concern, is covered, thus increasing the likelihood that every MS position will generate enough multipath components between itself and at least a couple of BSs. The deployment also aligns with the idea of densification for boosting capacity in urban centers. The BS deployment for the city center is shown in Figure 2, below.  
Because of the random placement of the MSs, some were situated in places that could not receive any useful signal, like in court yards. This meant that, no ray data was generated for those links and  
\begin{table}
\begin{tabular}{l l} \hline \hline  & **Ray-Tracer Output Data** \\ \hline
1. & Easting coordinate of BS (\(x\) coordinate) \\
2. & Northing coordinate of BS (\(y\) coordinate) \\
3. & Height of BS (\(z\) coordinate) \\
4. & Easting coordinate of MS \\
5. & Northing coordinate of MS \\
6. & Height of MS \\
7. & Frequency \\
8. & Transmit power \\
9. & Time delay \\
10. & Received power \\
11. & Phase \\
12. & Elevation AOD \\
13. & Azimuth AOD \\
14. & Elevation AOA \\
15. & Azimuth AOA \\ \hline \hline \end{tabular}
\end{table}
Table 1: List of ray-tracer outputs.  
Figure 2: Base station deployment showing the coverage radius.  
consequently those mobile positions were excluded from the study. In all ray-tracing data generation, the parameters are chosen to match those of the massive MIMO testbed at Bristol University [12]. Key outputs from the ray-tracer, that are used in this study, are the BS and MS locations (x and y coordinates), the azimuth AOA at BS, the received power and the time delay, for each ray or path.