 designs Flexible IAB integrated Non-terrestrial network Broadcast enhancements framework access/ backhaul (i.e., satellites) LTE integration Private Networks, SON Rel-15 deployment learning, Sidelink in unlicensed eMBB enhancements, XR, others spectrum Figure 16.13 - 3GPP specifications and satellite communication Figure 16.13 shows that NTN-related specifications started with R-17 and R-18 adds enhancements to it. 3GPP R-17 started support for NTN and that has led to greater adoption of satellite communication with 5G by service providers. R-18 will add support for cellular drones. 5G and Satellite Communications R-17 supports bent-pipe and transparent architecture for satellite communication. This implies the information transmitted from earth to the satellite is sent right back. Pictorially, i creates a shape like a bent pipe, as shown in Figure 16.14. This is the simplest form of satellite communication. The satellite may amplify the signal received from earth. The satellite does not do any other complex processing to the signal, keeping its systems simple. The satellite acts like a passive repeater in this case. Ground Station Receiver BENT PIPE SYSTEM Sender Figure 16.14 - Satellite bent-pipe architecture The LEO Globalstar satellites use bent-pipe technology (https : //globalcomsatphone. com/learn-about-globalstar-bent-pipe-and-path-diversity-satellite- technology-globalcom). Bent Pipe Crosslink Ground Satellite Ground Satellite Station Phone Station Phone Figure 16.15 - Satellite transmission technology The architecture of 5G and satellite communications Let us look at the impact of a voice call using bent-pipe versus crosslink technology, as shown in Figure 16.15. The latency between the satellite phone and the landline would be lower due to a single satellite hop. Globalstar and Inmarsat use such bent-pipe technology. On the other hand, Viasat and Iridium use crosslink technology, which can reduce the quality of voice communication and add latency for certain scenarios as the signal transmission time m