3D Cloud-RAN Functional Split to Provide 6G Connectivity on Mars

The Mars Helicopter Scout left a milestone in the history of the mankind by successfully completing the first flight on Mars. This achievement opens up to the possibility of having many unmanned aerial vehicles (UAVs) acquiring data from the Martian surface along with firmly anchored machines on ground, such as moving rovers or static landers. Moreover, it is no surprise that space agencies are also paving the way for the first human landing on the Red planet. In this context, it becomes needed to support future missions by providing connectivity to the whole Martian surface in order to allow in-situ wide band data exchange between nodes - user equipments (UEs) - composing the overall network. However, it seems tough to move common mobile terrestrial infrastructures on Mars and install them on-ground or implement them on limited-resource machines, as well as to guarantee everywhere and anytime on-demand connectivity. Thus, this paper will investigate the alternative solution of developing an autonomous Martian space ecosystem, through which globally inter-connect the UEs. UAVs and, eventually, high altitude pseudo satellites (HAPS), will act as radio unit (RU) and, partially, as distributed unit (DU) of a cloud radio access network (CRAN), while small satellites platforms, such as CubeSats (CS), placed in orbit will embark the majority of the computational load by performing the remaining DU and centralized unit (CU) functions. The proposed 3D network configuration, which looks towards a “Beyond 5G” infrastructure, or even 6G, will start by supposing very low Mars orbit (VLMO) in which CubeSats will be deployed. The design will then proceed through the installation process of CRAN on drones and CubeSats, while respecting strict latency and bandwidth requirements imposed by the Common Public Radio Interface standard (CPRI) at the fronthaul (FH) to allow low PHY-layer splitting options. A link-budget evaluation will then be proposed for the drone-to-Cubesat link. End-to-End (E2E) performance results will be shown in terms of coded BER between the UEs and the virtualized base station (BS), obtained by correlating the number of executable LDPC decoding iterations at CubeSat side and the signal-to-noise ratio (SNR) achievable over two specific areas of the Gale crater.