Inter-segment gateway selection for transmission energy optimization in space-air-ground converged network

Inter-segment gateway selection, as a critical issue for data delivery from ground segment to satellite via air network segment, is of great challenges for the design of space-air-ground converged networks (SAGCNs), especially for the transmission energy optimization due to the presence of unreliable or lossy wireless link in air network. To the best of our knowledge, it is an entirely new problem, since existing works on gateway selection mainly focused on one single network segment and gave no consideration to other segments. It is also noted that, we are the first to study the gateway selection problem with the objective of minimizing the transmission energy. Toward this end, in this paper, we formulate the issue of inter-segment gateway selection as a constrained optimization problem and propose two algorithms, i.e., an optimal enumeration algorithm (OEA) and a simulated annealing based algorithm (SOA). Extensive experiments based on different link error rate and relative velocity settings have been conducted and as validated by our numerical results, OEA can obtain an optimal result with extremely high computational complexity and SOA is able to achieve a near-optimal solution with much lower computational complexity.