Deployment of NB-IoT NTN core network functions on Software Defined Radio (SDR) nanosatellites: approach and performance assessment

According to forecasts, around 10 billion connected devices in the world will exchange data over the Internet by2028 and the significant connections increase threatens to congest terrestrial networks. These devices will mainly beembedded, controlled by smart software and operated in the cloud, integrating the Internet of Things ecosystem. Addi-tionally, current terrestrial infrastructures do not meet novel IoT requirements: remote access areas, multiple networkdomains crossing and adaptable latency and bandwidth. To provide global and ubiquitous coverage, the 3GPP stan-dardizes in rel-17 the concept of Non-Terrestrial-Networks. The term includes, among others, Non-Terrestrial nodessuch as GEO, MEO and LEO satellites. Lately, LEO satellites have contributed to consolidate the New Space indus-try opening new business opportunities by providing services using low-cost CubeSats. Despite offering importantbenefits compared to GEO (e.g. lower latency and propagation loss), LEO still has challenges to face related to com-munication discontinuity (intermittent satellite-to-ground links). Global region coverage is achieved through satelliteconstellations; however, the main concern is the non-guarantee of simultaneous contact from UE to the Ground StationNetwork via the satellite. While 3GPP rel-17 specs have centered on the specification of satellites using transparentpayload, the use of regenerative payloads has not precluded and has a central role in the technology roadmap. Re-generative payloads envision to embark part of the NF within the satellite, giving multiple enhancements (e.g. lowerlatencies, Store-and-Forward operation, in-satellite local loop communications and edge computing). Onboard func-tions may include radio access functions, such as eNB/gNB, as well as core NF, which enables direct satellite responseto UE. This paper provides a performance analysis of a deployment of core NF in a regenerative payload with a Soft-ware Defined Radio based on FPGA technology for nanosatellites. Measures are obtained and contrasted against aRPi4 board by running a tailored Evolved Packet Core (EPC) with NB-IoT NTN support.Peer ReviewedPostprint (published version