NOMA Application to Satellite Communication Networks for 5G: A Comprehensive Survey of Existing Studies

Abstract

The 4th generation of communication networks (4G) seems limited and unable to satisfy the growing networks’ performances demands of new intended communication services such as the internet-of-things (IoTs). The 5th generation of communication networks (5G) has therefore been envisaged to fill the gap. The non-orthogonal multiple access (NOMA) technology and the satellite communication have been identified as key enabling technologies for the achievement of 5G networks. There are many ongoing NOMA related works for 5G; however, the few existing reviews mostly discuss works that apply NOMA to terrestrial networks. This paper therefore, gives a comprehensive and up-to-date review of existing works applying NOMA to satellite communication networks. More precisely, it presents studies that have either designed or do performance analysis of NOMA-based multibeam satellitesystems (MBSSs) or integrated satellite-terrestrial networks (ISTNs). The surveys presented showed that the application of NOMA to satellite communications for 5G is starting to gain considerable interest. Most of the current PD-NOMA design works attempt to maximize the system capacity (sum-rate), and most of the current PD-NOMA performance analysis works demonstrate the superiority of NOMA over OMA through Ergodic Capacity and Outage probability estimations. The surveys also showed that this field is still quite opened for research, with issues such as user-fairness maximization, satellite capacity improvement, ground-surface moving beams (for LEOs and MEOs satellites) and multiple gateways combination … etc. remaining prospective research areas to be explored.