## 5 Results and Discussion  
The results of the simulation are presented in Table 2, including the test cases, the used algorithm, expected SNRs, the hybrid average bitrate (obtained when switching from one channel to another within the same test case), the percentage of the channel 1 usage (satellite) and the average rejection rate of the sent packets. The presented results show several important implications. Firstly, there is an expected increase in the average bitrate for the hybrid channel communication with the increase in the average SNR, which is to be expected. Secondly, the average rejection rate is 0 for both the LSTM and outdated information for the cases with the expected SNR being lower or equal to 6 dB. This is an interesting phenomenon as there is a rejection percentage for higher SNRs, even if higher SNR values are considered a more favorable communication condition. This is the result of two different factors. Firstly, for the lower SNR values, the lower MODCODs are more frequent, and according to Table 1, for the considered  
Figure 7: PC where HUT is run, and two Zynq UltraScale+ RFSoC where T/R and Channel modules are deployed. simulation parameters, no packets are to be sent for the lowest four considered MODCODs. If the decision is not to send data, then there is no data rejection. In addition to this, the second factor that causes no data rejection is the margin used to keep the transmission error rates below 1% for both the outdated information and LSTM. These margins lower the selected MODCODs and therefore make them often fall in the range of the low MODCOD values for which no data are sent. This lowers the rejection rate and also lowers the communication speed. In contrast, for the higher expected SNRs, an increase in the average speed can be seen, and the rejection rate rises above 0 but still falls under 1%. This is to be expected as higher MODCODs are being used, but the limit of the 1% transmission error rate that is used for margin determination can be seen in the results by the rejection rate falling under 1%. It is also important to note that the performance of LSTM is consistently better than the outdated information approach, which can justify the usage of LSTM, but the improvements are not equal for all test cases. For the test case with the expected SNR of 15 dB, there is no clear improvement in the second decimal of the average speed. There is, however, a decrease in the rejection rate from 0.6 to 0.47 percent. It can also be seen that for this case, the satellite channel is used very little (under 1% of the time), and hence, the terrestrial channel has the conditions that suit a very high MODCOD without the need for complex decision making. The conclusion is that the main contribution of LSTM implementation is around 9 or 12 dB, as there is the most usage of the satellite communication channel, and the widest range of MODCODs is considered for communication. Going more in depth into test cases 4 and 10 to see the details of the simulation process, Figure 8 depicts the rejected frame percentage and the information bitrate over time. For both types of graphs displayed in Figure 8, the averages are computed at a time interval of 1 s to make the data more visually interpretable. It can be seen that the information bitrate over time has the same shape for test cases 4 and 10. The terrestrial channel is superior to the satellite channel, and the hybrid channel communication exhibits an increase when compared to the terrestrial one. These shapes simply show that the trends of MODCOD selection are not deformed or changed by a more complex decision-making algorithm such as LSTM but rather simply shift to higher values. Because of this, the axis range on the information bitrate are intentionally left to be different so that it can be seen that the results between algorithms are similar in shape but that the LSTM provides an increase in the mean