## 4 Power Restriction Impact in the 5G-RANGE as TVWS System
The results of the field measurements at the location referred to as \"MS_CafezalManoela\", establishing a communication link with a distance of 14.71 km to the BS, are presented in Table 12. Tests were conducted at this location considering the BS configured to transmit, in addition to the initial \(P_{\text{TX}}\) of 1 Wp, power levels of 2 Wp and 4 Wp, since the initial \(P_{\text{TX}}\) did not provide the system with full operational capacity. However, the 1 Wp \(P_{\text{TX}}\) enabled the system to operate with an MCS featuring 256-QAM mapping and Polar code 2/3, providing support for a bitrate of 24 Mbps for the system operating with a 6 MHz BW. Considering a BW of 24 MHz, the bitrate\({}_{4\text{ Ch}}\) of the system amounts to 96 Mbps, a value close to that obtained in the reference test of 5G-RANGE. Therefore, it is estimated that the maximum distance for the system to achieve a throughput of approximately 100 Mbps, for a 1 Wp \(P_{\text{TX}}\), is 14.7 km. Increasing the transmission power to 2 Wp and 4 Wp allowed the system to operate at the \"MS_CafezalManoela\" location with the MCS providing the highest throughput in the system, namely, 120 Mbps. Table 13 presents the results of the tests conducted at the most distant location, which is at a straight-line distance of 38.34 km from the BS, referred to as \"MS_Pedralva\". At this location, it was possible to establish a reception link using QPSK mapping and Polar code with a 1/2 rate in the 5G-RANGE system, for a \(P_{\text{TX}}\) of 1 Wp. This configuration supports a throughput of 4 Mbps for a transmission channel with a 6 MHz BW or 16 Mbps for a channel with a 24 MHz BW. Additionally, since this configuration provides the lowest MCS and the minimum throughput supported by the 5G-RANGE system, it can be \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Local MS** & \(P_{\text{RX Ant.}}\) [**dBm**] & **SNR [dB]** & **MCS** & **Bitrate [Mbps]** & **Bitrate\({}_{4\text{ Ch}}\) [Mbps]** \\ \hline \hline \(\text{Loteamento}\) & \(-64.7\) & 34.1 & 256-QAM—Polar 5/6 & 30 & 120 \\ \hline \(\text{DeltaBlack}\) & \(-68.6\) & 32.8 & 256-QAM—Polar 5/6 & 30 & 120 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Results of reception tests for the 5G-RANGE (TVWS) system at the locations MS_Loteamento and MS_Delta Black. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \(P_{\text{TX}}\) [**Wp**] & \(P_{\text{RX Ant.}}\) [**dBm**] & **SNR [dB]** & **MCS** & **Bitrate [Mbps]** & **Bitrate\({}_{4\text{ Ch}}\) [Mbps]** \\ \hline \hline \(1\) & \(-76.6\) & 25.6 & 256-QAM—Polar 2/3 & 24 & 96 \\ \hline \(2\) & \(-73.1\) & 28.84 & 256-QAM—Polar 5/6 & 30 & 120 \\ \hline \(4\) & \(-70.3\) & 31.15 & 256-QAM—Polar 5/6 & 30 & 120 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Results of reception tests for the 5G-RANGE (TVWS) system at the location MS_CafezalManoela. concluded that, at the \"MS_Pedralva\" location, the system operated at the coverage edge for the configured 1 Wp \(P_{\text{TX}}\), which is the currently applicable transmission power limit for TVWS systems. Tests were executed by increasing the total transmission power to 2 Wp, 4 Wp, and additionally, 8 Wp. Under these conditions, it was possible to achieve a communication link supporting a throughput\({}_{\text{4 Ch}}\) of 28 Mbps, 48 Mbps, and 52 Mbps, respectively. This represents an increase equivalent to 1.75 times, 3 times, and 3.25 times, respectively, compared to the throughput supported with 1 Wp. The results of these tests showed that, for applications in rural areas, the power limitation imposed on TVWS may restrict coverage, which reinforces the need for regulatory adjustments that consider not only the protection of DTV, but also the viability of TVWS for long-distance communication. Figure 14d shows the MS at the \"MS_Pedralva\" location during the field tests, and Figure 14a-c illustrates the reception spectrum at the locations \"MS_DeltaBlack\", \"MS_CafezalManolea\", and \"MS_Pedralva\" for the BS operating with a power of 1 Wp. The \(P_{\text{RX Ant.