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Frequency and Time-Space Duality Study for Multibeam Satellite Communications

In this paper, we investigate two new candidate transmission schemes to replace current ones in satellite communication systems. They operate in different domains (frequency and time-space), and we want to know which domain shows overall best performance. The two new transmission schemes are: Non-Orthogonal Frequency Reuse (NOFR) and Beam-Hoping (BH). We propose a novel formulation of the Signal-to-Interference-plus-Noise Ratio (SINR) and spectral efficiency of these two schemes and prove the theoretical duality between them. Further, we also develop a general methodology to include the technological constraints due to realistic implementation, which is common for the two domains and obtain the main factors that prevent the two technologies be in practice dual of each other (what we have called the technological gap). Moreover, we solve the frequency/time-space resource optimization problem with two different cost functions for an asymmetric traffic distribution. Both Gaussian codes and current state-of-the-art adaptive coding and modulation transmission over time division multiplexing (DVB-S2) are assumed in the simulation. It is shown that the Beam Hopping system turns out to show a less complex design and performs better specially for non-real time services.