Capacity maximization based power loading analysis for digital channelized satcom systems

For digital channelized frequency division multiple access based satellite communication (SATCOM) systems, it is a challenging but critical issue to improve the transponder power and spectrum efficiency simultaneously under limited and non-linear high-power amplifier conditions. In this paper, different from the traditional link supportability designs aiming at minimizing the total transponder output power, a maximal sum Shannon capacity optimization objective is firstly raised subject to link supportability constraints. Furthermore, an efficient multilevel optimization (MO) algorithm is proposed to solve the considered optimization problem in the case of single link for each terminal. Moreover, in the case of multiple links for one terminal, an improved MO algorithm involving Golden section and discrete gradient searching procedures is proposed to optimize power allocation over all links. Finally, several numerical results are provided to demonstrate the effectiveness of our proposals. Comparison results show that, by the MO algorithm, not only all links´ supportability can be guaranteed but also a larger sum capacity can be achieved with lower complexity.