## 4 Experiment Results and Analysis  
### Experiment Setup  
Our experimental system consists of multiple components, as shown in the Figure 4. The signal source is Gongjin 5G Sub-6 GHz Small Cell base station, the user equipment is Huawei P40, and the PC is HP Laptop equipped with Inter (R) Core (TM) i5-8250U CPU @ 1.60 GHz processor. The PC installs Pilot Pioneer Tools version 10.5.8.32 and HI-SILICON driver software. The user equipment stores the original radio signal into the PC through the USB cable, and we use the data analysis tool Pioneer to export the required measurements for constructing fingerprinting database.  
Figure 4: Experimental equipment: (**a**) 5G small base station. (**b**) PC and user equipment.  
In order to verify the validity of MVF and proposed method in various scenarios, we give the experimental results of two typical indoor environments. The positioning area is divided into several reference points and test points evenly. The black dots represent reference points and the red stars represent test points. Establishing a coordinate system with the first reference point as the origin, we measure and record the coordinates of other reference points and test points. UE is placed at each reference point and test point to capture SSS for establishing fingerprinting database. The two rooms are described as follows and as shown in Figure 5.  
Room A: a typical meeting room shown in Figure 4(a). The size of room A is 7 m \(\times\) 6 m with a table placed in the center, and there is a projector in the front of the room and a cabinet in the back. The 5G base station is located in the lower left corner of the room instead of the center to avoid isotropy. The base station towards the room with a height of 2 m. The UE is placed horizontally on a tripod with a height of 1 m, and most positions are in LOS environment. The positioning area is divided into 41 reference points, and each point is evenly deployed in a grid of 1 m \(\times\) 1 m. 23 test points are evenly selected. We collect data packets at each point for 2 min and the fetch rate is 200 ms/samples.  
Room B: a typical office room shown in Figure 4(b). The size of room B is also 7 m \(\times\) 6 m and the room is crowded with tables and computers, which forms a complex radio transmission environment. The 5G base station is in room A, which locates out of the room B with a height of 2 m. The signal propagates in room B forming a pure NLOS environment. The UE is placed horizontally on a tripod with a height of 1 m. The positioning area is divided into 30 reference points, and each point is evenly deployed in a grid of 1 m \(\times\) 1 m. 17 test points are evenly selected. We collect data packets at each point for 2 min and the fetch rate is 200 ms/samples.  
The average error \(\varepsilon\) and 80% quantile of cumulative distribution function (CDF) are used as the performance metric for different positioning algorithms. Assuming that the true position of the test point is \((x_{t},y_{t})\) and the estimated position is \((x_{e},y_{e})\). The root square error (RSE) is calculated as:  
\[\text{RSE}=\sqrt{\left(x_{t}-x_{e}\right)^{2}+\left(y_{t}-y_{e}\right)^{2}} \tag{18}\]  
Figure 5: Map of positioning area: (**a**) Room A. (**b**) Room B.  
For \(M\) locations, the average error is calculated as:  
\[\varepsilon=\frac{\sum_{m=1}^{M}\text{RSE}_{m}}{M} \tag{19}\]