# 5G NPN Performance Evaluation for I4.0 Environments
## 4 I.4.0 and 5G Framework Evaluation Measurements
Based on the measurements and other parameters, a slicing schema can be recreated for an I4.0 scenario. A graphical representation of the downlink bit rate vs. RSRP for the various TDD schemes is shown in Figure 5. The uplink bit rate and the mean RTT for each TDD are shown in Figures 6 and 7, respectively. From Figure 7, we can observe that the RTT was smaller due to the shorter symbol period, which allowed for more frequent transmissions and, thus, reduced the delay. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**TDD\_1 7 dl 2 ul**} & \multicolumn{3}{c}{**TDD\_2 6 dl 3 ul**} & \multicolumn{3}{c}{**TDD\_3 2 dl 2 ul**} \\ \hline
**RSRP** & **Downlink** & **Uplink** & **RTT** & **Downlink** & **Uplink** & **RTT** & **Downlink** & **Uplink** & **RTT** \\
**(dBm)** & **(Mbps)** & **(Mbps)** & **(ms)** & **(Mbps)** & **(Mbps)** & **(ms)** & **(Mbps)** & **(Mbps)** & **(Mbps)** & **(ms)** \\ \hline \(-75\) & 137.93 & 40.61 & 12.72 & 116.42 & 63.73 & 13.45 & 91.5 & 82.79 & 12.68 \\ \hline \(-90\) & 124.03 & 38.39 & 13.41 & 105.09 & 48.06 & 12.53 & 82.73 & 76.76 & 12.51 \\ \hline \(-100\)In order to compare the experimental bit rates with the theoretical ones, we used Formula (1) and its online version presented in [35]. The calculation was based on the 3 GPP TS 38.306 standard: NR User Equipment (UE) radio access capabilities, and used the formula to obtain a 5G NR throughput data rate in the DL (downlink) and UL (uplink) directions. To obtain the correct result, it is necessary to enter such important parameters as the mode of the 5G network, number of aggregated carriers, number of MIMO layers, bandwidth, frequency range, modulation type, etc. For the experimental system that we used, and considering an excellent quality (\(-75\) dBm), the theoretical bit rates were about \(12\)-\(15\%\) higher than the experimental ones for the TDD modes under consideration. \[\text{Data rate }(\text{in Mbps})=10^{-6}\sum_{j=1}^{J}\left(v_{Layerz}^{(I)} \cdot Q_{m}^{(I)}\cdot R_{max}.\frac{N_{PRB}^{BW(f),\ \mu}\cdot 12}{T_{s}^{\mu}}(1-OH^{(f)})\right) \tag{1}\]  
Figure 6: Uplink rates for different TDD values. Figure 7: RTT measurements for different TDD schemes. Our conclusion is that a low-cost 5G NPN may be used in an I4.0 environment to provide connectivity. The inherent flexibility of 5G makes it ideal to support a variety of machines and IoT with different requirements on the factory floor. In comparison to other methods presented in the literature, in [36], the authors considered direction-finding in mmW 5G networks by means of reported beam-based DL RSRP measurements; however, they did not report any measurements regarding the DL, UL, or RTT performance. Similar methods presented in [37; 38] analyzed the error in predicting the RSRP based on the past channel measurements, and proposed a 3D UE positioning method for 5G mmW networks by exploiting DL beam-formed RS from Base Stations [39], but their results were limited to reporting of the RSRP-to-dB correlation of the 5G systems. This work extends these studies on 5G NPN networks, while providing indicators of the performance of a real-world system under factory-floor-like network conditions.