## 4 Power Restriction Impact in the 5G-RANGE as TVWS System  
The results presented in this section refer to the second stage of field tests, considering long distances, and investigate the impact of the transmission power limitation applicable to TVWS systems on coverage and link quality. The secondary network is the 5G-RANGE system, and the tests consider a total transmission power (\(P_{\text{TX}}\)) restriction of 1  Wp delivered to the transmission antenna, for a transmission channel with a 6 MHz BW, based on Anatel's resolution [33]. As a key reference parameter for analyzing the impact of power limitation on 5G-RANGE coverage, previous field tests were conducted when no power limitation was defined, as detailed in [45]. The channel BW used in previous and reference tests was 24 MHz, and the \(P_{\text{TX}}\), considering a PAPR of 10 dB, was approximately 50.8 dBm or 120.2 Wp. With these configurations, the system operated with a throughput of 102 Mbps over a link distance of 50 km. It is worth noting that this was not the maximum coverage limit of the system under the described conditions. In the reference test, the goal was to verify long-range coverage while maintaining support for a throughput of 100 Mbps. Table 11 presents the results of field tests related to the 5G-RANGE system operating under the current restrictions imposed on TVWS systems. The measurements were per \begin{table}
\begin{tabular}{c l c c c} \hline \hline  & \(P_{\text{TX}}\) **TVWS (CH28) [Wp]** & \multicolumn{2}{c}{**4**} \\
**DTV** & **Filter\({}_{\text{RX}}\) (CH28)** & & **No** & \\
**Channel** & **Att. after LNA\({}_{\text{RX}}\) (dB)** & **4** & **3** & **2** \\  & **LNA\({}_{\text{RX}}\)** & & **On** & \\ \hline  & \(P_{\text{RX}}\) DTV (CH29) [dBm] & \(-76.9\) & \(-76.8\) & \(-76.8\) \\
29 & \(P_{\text{RX}}\) TVWS (CH28) [dBm] & \(-51.2\) & \(-50.0\) & \(-49.0\) \\  & PR\({}_{(n\,+\,1)}\) [dB] & \(-30.1\) & \(-31.1\) & \(-31.8\) \\  & PR\({}_{(n\,-\,1)}\) [dB] & \(-25.7\) & \(-26.8\) & \(-27.8\) \\ Interf. & ACPR\({}_{\text{UPPER}}\) [dB] & \(30.1\) & \(31.1\) & \(31.8\) \\ \(n+1\) & ACPR\({}_{\text{LOWER}}\) [dB] & \(25.7\) & \(26.8\) & \(27.8\) \\ e & \(P_{\text{RX}}\) INT. (CH30) [dBm] & \(-46.8\) & \(-45.7\) & \(-45.0\) \\ \(n-1\) & DTV STB Status 1 & OK & NOK & NOK \\  & DTV STB Status 2 & c OK & OK & NOK \\  & DTV STB Status 3 & OK & OK & OK \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Additional test results with \(n+1\) and \(n-1\) interference at the MS_Loteamento location. formed at locations closest to the BS, specifically at MS_Loteamento and MS_DeltaBlack, with straight-line distances from the MS of 5.68 km and 7.35 km, respectively. In both links, it was possible to establish reception with a modulation and coding scheme (MCS) configuration that provides the maximum data throughput supported by the system. This configuration involves using the 256-QAM mapping scheme and employs Polar FEC encoding with a coding rate of 5/6. Consequently, a bitrate of 30 Mbps was achieved for a channel with a BW of 6 MHz. It is important to emphasize that the criterion used for selecting the configured MCS at each location is related to achieving a BER of 0, measured and observed within a time interval of 5 s after resetting the system. Extrapolating to a transmission using four UHF channels, totaling a BW of 24 MHz, which is the maximum BW supported by the 5G-RANGE system, the MCS provides support for communication with a bitrate\({}_{4\text{ Ch}}\) of 120 Mbps. Additionally, in Table 11, the received power (\(P_{\text{RX Ant. }}\)) captured by one of the system's antennas and the signal-to-noise ratio (SNR) values are observed.