## 4 Solution of the Fiber Optical Repeater
### System Infrastructure and Link Budget
#### 4.1.3 An Add-on Solution Consisting of a New 5G FR on the Empty Side  
Add-on 5G fiber repeater products can be deployed with new 1-5/8 cables in tunnels, platforms, and buildings through combiner share antennas without disturbing the existing architecture, as shown in Figure 13.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**System** & **Area A** & \(\underline{\mathbf{SS_{req}}}\) & **Area B** & \(\underline{\mathbf{SS_{req}}}\) & **Area C** & \(\underline{\mathbf{SS_{req}}}\) & **Coverage (\%)** \\ \hline LTE-A & & \(\underline{\geq}-80\) & Electric escalator, Parking area & \(\underline{\geq}-85\) & Elevator control & \(\underline{\geq}-85\) & 95\% \\  & & & Shopping mall, Ticket selling & & & & \\
5G & Tunnel, Station, Platform, & \(\underline{\geq}-93\) & area, & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ LTE-A & & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 6: Quality plan for acceptable indoor coverage requirements.  
Figure 10: TRA-employed system scope overview.  
Figure 11: Building coverage in a TRA for SCE system novel network architecture.  
Figure 12: Improving overall passive and massive data efficiency in a TRA for SCE system novel network architecture.  
Figure 13: LTE solutions employed in a tunnel without disturbing the SCE system’s novel network architecture.  
For LTE TX/RX combined with add-on 5G products via TX/RX combining, new add-on antennas are located at the leakage end through existing 1-1/4 leakage cables, as shown in Figure 14.  
The tunnel-centric coverage of LTE systems based on existing RFS leaky cables for DAS plans is described below:  
We assume that output CPICH for LTE up to four carriers is +24 dBm (Composite + 34 dBm). The 250 m LCX 11/4: longitude loss is 20.4 dB.  
If an 11.5 dB Yagi antenna is added at the end of 250 m LCX, the EIRP is \(24\,-\,20.4\,-\,3.5\,-\,0.5\,+\,11.5\,=\,11.1\) dBm.  
We assume Wagon loss and crowd loss = 25 dB. The received signal inside Wagon from the Yagi antenna is shown in Table 7.  
The use of multi-RAT to establish an automated neighbor relation function (ANRF) and the configuration of physical cell identity (PCI) for the optimization of mobility and data efficiency in multiple radio access and layer technology (Multi-RAT-Layer) [23; 24; 25] are shown in Figure 15.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**LTE Signal Level with Reference Distance** & & & & & & \\
**from Yagi Antenna for 11/4\({}^{\prime\prime}\) LCX** & **5 m** & **50 m** & **100 m** & **150 m** & **200 m** & **250 m** \\ \hline
11 dB Yagi Antenna @end of 250 m LCX & \(-67.2\) & \(-87.2\) & \(-93.2\) & \(-96.8\) & \(-99.3\) & \(-101.2\) \\ (Near side) dBm & & & & & & \\ \hline
11 dB Yagi Antenna @end of 200 m LCX & \(-63.1\) & \(-83.1\) & \(-89.1\) & \(-92.7\) & \(-95.2\) & \(-97.1\) \\ (Near side) dBm & & & & & & \\ \hline
5 m with EIRP 11.1 dBm = \(-67.2\) dBm. 50 m with EIRP 11.1 dBm = \(-87.2\) dBm. 100 m with EIRP 11.1 dBm = \(-93.2\) dBm. 150 m with EIRP 11.1 dBm = \(-96.8\) dBm. 200 m with EIRP 11.1 dBm = \(-99.3\) dBm. 250 m with EIRP 11.1 dBm = \(-101.2\) dBm. & & & \\ \hline \hline \end{tabular}
\end{table}
Table 7: Summary of received LTE signal for Leaking cable and Yagi Antenna.  
Figure 14: Existing RFS leaky cable for DAS plan.