DYNASAT is happy to announce that three papers that were written during project runtime were recently accepted for presentation at two international conferences.
The first conference paper was recently accepted for presentation at IEEE Aerospace Conference from Mar 4 – Mar 11, 2023, in Montana:
Title: Co-channel Spectrum Sharing between Terrestrial and Satellite Networks
Authors: H. Kokkinen, Fairspectrum, A. Piemontese, University of Parma
Abstract: In the paper, the authors study the ideas, plans, standards, and regulation efforts to share spectrum between terrestrial and satellite radio spectrum to support Non-Geo-Stationary Orbits (NGSO) satellite 6G communication. They pay specific attention to different scenarios of terrestrial cells overlapped by several satellites. They show how cognitive, database-driven control of earth-fixed satellite beams enables co-channel DSA of NTN and TN, in the way that NTN downlink does not decrease the TN downlink capacity. Moreover, they focus on the case where TN has a priority over the satellite network. The performance of the designed system is evaluated in terms of interference, capacity, coverage, and spectrum utilization efficiency for cooperative and non-cooperative sharing.
In addition to this paper, the following two conference papers were accepted for presentation at the 11th Advanced Satellite Multimedia (ASMS) Conference from Sept 6 – Sept 8 in Graz, Austria:
Title: Joint Graph-based User Scheduling and Beamforming in LEO-MIMO Satellite Communication Systems
Authors: D. G. Riviello, B. Ahmad, A. Guidotti, A. Vanelli-Coralli, University of Bologna
Abstract: In this paper, a Low earth orbit (LEO) High-Throughput Satellite (HTS) Multi-User multiple-input multiple output (MIMO) system is considered. With the objective of minimizing inter-beam interference among users, the paper proposes a joint graph-based user scheduling and feed space beamforming framework for the downlink. First, the authors construct a graph where the vertices are the users and edges are based on a dissimilarity measure of their channels. Secondly, they design a low complexity greedy user clustering strategy, in which they iteratively search for the maximum clique in the graph. Finally, a Minimum Mean Square Error (MMSE) beamforming matrix is applied on a cluster basis with different power normalization schemes. A heuristic optimization of the graph density, i.e., optimal cluster size, is performed to maximize the system capacity. The proposed scheduling algorithm is compared with a position-based scheduler, in which a beam lattice is generated on ground and one user per beam is randomly selected to form a cluster. Results are presented in terms of achievable per-user capacity and show the superiority in performance of the proposed scheduler with respect to the position-based approach.
Title: Evaluation of MU-MIMO Digital Beamforming Algorithms in B5G/6G LEO Satellite Systems”
Authors: M. R. Dakkak, D. G. Riviello, A. Guidotti, A. Vanelli-Coralli, University of Bologna
Abstract: The paper proposes a beamforming algorithm based on maximizing the users’ Signalto-Leakage-and-Noise Ratio (SLNR) served by a Low Earth Orbit (LEO) satellite. It investigates and assessed the performance of several beamforming algorithms, including both those based on Channel State Information (CSI) at the transmitter, i.e., Minimum Mean Square Error (MMSE) and Zero-Forcing (ZF), and those only requiring the users’ locations, i.e., Switchable Multi-Beam (MB). Through a detailed numerical analysis, the paper provides a thorough comparison of the performance in terms of per-user achievable spectral efficiency of the aforementioned beamforming schemes, and it shows that the proposed SLNR beamforming technique is able to outperform both MMSE and ZF schemes in the presented SatCom scenario.