## 6 Results
This signifies that the transmission of Msg3 and Msg4 is influenced by satellite delays, as shown in Figure 11, potentially altering the timing of this procedure. The configuration of timers is crucial to control the message exchange implicated in the RA procedure. For this work, we must emphasize the RA Contention Resolution timer, which corresponds to the in-house implementation of OAI [58]. This timer is configured in the gNB to measure the time interval between the transmission of Msg2 and the reception of the ACK of Msg4. In this way, the gNB is capable of detecting any failed RA on the UE side to release its allocated radio resources and prevent their wastage with the retransmission of Msg4. In the midhaul architecture, the previous timer expires regardless of its value, partly due to the non-real-time implementation of RFS Simulator explained in Section 4. This occurs because the timer is governed by RFS Simulator's temporality, and the transmission of Msg3 and Msg4 is subject to Starlink's latency. The result is that the timer perceives Starlink's latency, which spans tens of milliseconds, as well as thousands of milliseconds, inevitably exceeding its limit. Considering the causes of this situation, we opted to disable this non-standard timer, achieving the successful completion of the RA procedure. In our single-UE NTN scenario, the disabling of this timer has no effects. However, the gNB could experience problems when managing radio resources if various UEs fail the RA procedure in a multi-UE scenario. In that case, the gNB is not be able to allocate resources, resulting in the automatic rejection of new registration attempts. Finally, the NR architecture performs the worst, as evidenced by the mean RTT, which exceeds one second, and the mean jitter, which reaches 366 ms. RFS Simulator transmits the I/Q samples, which would be normally sent to the SDR frontend, through a TCP socket. Although ZSTD compression significantly reduces the total traffic, a substantial number of samples must be still transmitted. The hypothesis posits that this large amount of traffic transmitted, added to the delay introduced by the compression processing (depicted in Figure 10), is the main cause of the degradation. It could be causing most of the degradation, resulting in RFS Simulator being the bottleneck that makes the results obtained from the relay of NR contrast drastically with those of the rest of the architectures. In the NR architecture, the Internet Control Message Protocol (ICMP) packet involved in a ping measurement is progressively converted into several packets as it traverses the protocol stack, eventually reaching the physical layer. At this point, these packets are translated into I/Q samples and encapsulated in TCP by RFS Simulator. Consequently, a single ICMP packet triggers the transmission of multiple TCP packets over Starlink. Thisprocess amplifies the impact of the Starlink delay on the ping measurement, which is further accentuated by the additional increase in RTT introduced by ZSTD, as shown in Figure 10. For this reason, we conclude that RFS Simulator offers a straightforward and easy-to-deploy solution that enables UE registration on the network, albeit with limited service performance. The results presented in this section demonstrate the notable impact of NTN transparent architectures on user performance. Among the proposed architectures, NR suffers large delays exceeding one second in RTT, whereas backhaul and midhaul incur degradations of approximately 232% and 285% compared to the baseline TN, respectively.