Realizing the first standardized 5G NR NTN solution

eMBB-S services will be rolled out with NR NTN. The rollout of NR NTN involves development of the NR NTN waveform on both the UE and gNB side, O&M function and adaptations of the core to complete the system architecture. Beyond that, Network operators will need to license spectrum that is wide enough to provide the eMBB-S service (5-20 MHz), which is also a major challenge, especially for global coverage. In many cases new satellites need to be deployed into orbit. As a final requirement for deployment in scale: ITU must approve the submission for IoT NTN and NR NTN from 3GPP to be satellite components of IMT2020 (5G). There have already been lab demonstrations and in-orbit demos of parts of the system, along with satellite development and launches. It is difficult to predict when there is both a market request and we as an ecosystem have solved the technical challenges, but we are preparing the gNodeB physical layer for commercial operation in scale by 2026/2027.

The advantages of the regenerative architecture are three-fold. First, it limits the propagation time on the NR interface, which makes up the lowest protocol stack layers and this means a lower propagation delay and a higher throughput in effect. Second, the downlink does not have to carry the IQ of the signal and can instead be logic (ie bits) encapsulated in a more efficient waveform for the purpose of feeder-link transmissions. Third, the regenerative architecture offers new potential features, e.g. Device2Device loop-back calls through satellite without ground-segment (billing and setup with the core-network, but otherwise reduced latency i.e. higher throughput), store-and-forward functionality for satellites that are out of ground-station coverage, or even satellite network including satellites dedicated to core functionality that would provide low-latency core-network services to other satellites interconnected via ISL.

The 70/2 Mbps PHY-rate for DL and UL, respectively, are requirements for a satellite technology to be considered 5G. NR NTN may yield greater data-rates than that. The increased availability of bandwidth will mean more eMBB deployments with a wider channel bandwidth and along with that Ku-band deployments would be expected to work with directional antennas, which potentially could mean a better SNR for the UE-gNB interface. Together the increased channel bandwidth and SNR would mean a greater achievable data rate.

It would depend on the number of beams and the size of the LEO satellite. We would not expect a LEO satellite to project too many simultaneously active beams. Assuming then that there is sufficient power and space onboard, It is feasible to use ASICs and FPGA to optimize many algorithms in the DU, especially in L1 so it can run onboard.

Apologies for any confusion, this was an error in the Slide 15 table, the L+S band were introduced for both NR NTN and IoT NTN in a Release 18 work item. The extensions for L+S band are only for IoT NTN (1518-1525 MHz and 1668-1675 MHz). NR NTN saw the addition of 30 MHz channel BW in FR1 in Release 18.

In Release 19 there have been proposals for supporting UEs without GNSS, but some companies either do not believe it is feasible to support or that such a use-case is not worthwhile the work involved. So instead, one proposal for Release 19 is to support short GNSS outages. In Release 17 and Release 18 GNSS is assumed in the UEs, but the UEs can in theory be stationary over their lifetime and then be provisioned with their GNSS coordinate.

Theoretically, the flexible numerology and allocation of signals in NR means that signals (SSB, CORESET, SIBs) could be allocated within the 1 MHz of a "5MHz channel". There would need to be sufficient guard-band on the sides and the ratio of overhead of fixed DL-signaling would increase.

The coverage gap, and the prevailing economics of closing it, is the major driver of terrestrial operators in search of satellite partnerships. There is no doubt that satellite and terrestrial mobile operators will establish new partnerships in the future, which will lead to the convergence of services like mobile broadband and lead to various business models. However, there are some key factors that we must consider. Firstly, regulators are increasingly focusing on the topic of terrestrial and non-terrestrial convergence. Strategic decisions regarding spectrum utilization must be made to optimize network performance and minimize technical, administrative and regulatory obstacles. Secondly, the large scale convergency of 5G mobile broadband will progress at the same pace as the technology matures.