## 4 Discussion  
The results from the FSS-ES field test at an 85 m distance depicted the loss as 0%, and the bit error rate (BER) is 10\({}^{-6}\). No BER was obtained, although three carriers were considered in testing the transmitted power (TX) of 5G-BS and were reduced to 100 W. However, the received signal frequency for the new C-band LNB without filter (3.705 GHz), C-band LNB with filters (3836.27 GHz), and extended C-band with several filters (3.705 GHz) were all tested. The 5G carrier 1 (full load) and carrier 2 (full download) operated at 100 MHz GB. Carrier 1 (100% load), carrier 2 (100% load), carrier 3 (full download), and the 5G-BS were on at all times. A difference was observed between RF interference (RFI) and RFI*1, whereas FRI*1 denotes that the link passes but with a high BER. The interference is caused by the operator's 5G frequency allotment on the C-band satellite signal frequency. The FSS-ES measurements show that without a 5G signal, the signal intensity of the C-band satellite signal is around \(-\)81.7 dBm at an 85 m distance. However, when the 5G signal with 100 GHz GB is present, the interference signal exceeds 24.2 dB, and the signal intensity is around \(-\)79.9 dBm. It is important to note that the downconversion frequencies of the LNB range from 950 MHz to 1.65 GHz, and the 5G frequency allotment is between 3.4 and 3.5 GHz, which are close to the C-band satellite signal frequency. This could cause interference and affect the quality of the satellite signal. The broadband tuner is experiencing interference from the 5G signals in the operator's frequency allotment range, which is close to the C-band satellite signal frequency. When the signal travels through the LNB, the downconversion frequencies are 1.450 and 1.65 GHz, which may be causing the interference. The FSS-ES is able to block some of the interference caused by the 5G signals, but it is not able to fully reject or reduce the 5G signals to levels below which the satellite can receive them. As a result, the affected C-band satellite signals may need to be temporarily removed in order to resume broadcasting immediately. It appears that the FSS-ES successfully reduced interference using a filter technique for the extended C-band signals. Filter-1 with 100 MHz GB and low interference resulted in a minimal interference increase of 22 dB, while filter-2 with 100 MHz GB reduced the interference by 35.7 dB. Filter-5 reduced the interference to 31.9 dB. The LNB frequency range did not play a significant role in reducing the interference effect, as no interference was observed with 100 MHz GB for all types of LNB when paired with BPF with sufficient rejection. At a distance of 85 m or more, there was no remarkable effect on direct-facing FSS-ES, as no interference was observed with 100 MHz GB. The conducted Monte Carlo simulations of 5000 snapshots were performed for each scenario, with the FSS-ES parameters at an INR threshold of \(-\)12.2 dB to define the interference level and the INR cumulative distribution function (CDF) at a 15\({}^{\circ}\) elevation angle via 5G-BS in co-channel interference. We found that a minimum distance of 35 km is needed to maintain the INR of \(-\)12.2 dB, and significant changes were observed on the CDF plotlines for different elevation angles. The authors also investigated the effect of protection distance on the interference probability, the CDF probability for a 20 km protection distance. Also, we found that changing the elevation angle of 5G-BS may relieve the limitation on the protection distance if the protection distance cannot be maintained effectively. Furthermore, the authors investigated the adjacent interference probability using the spectrum emission mask for a protection distance of 0.6 km. They found that the FSS-ES is not affected by the 5G-BS because the spectrum emission mask features are lower than the adjacent interference. Finally, the authors determined the out-of-band emission mask level causing interference in the FSS-ES by adjusting the protection distance of 5G-BS to 0.6 km.