Capacity and loading analysis of digital channelized SATCOM system

Digital channelization techniques are widely used in current frequency division multiple access (FDMA) based satellite communications (SATCOM). In order to acquire a larger capacity and simultaneously satisfy the constraints including limited uplink Effective Isotropic Radiated Power (EIRP) and the minimum receiving E_b / N₀ at terminals, a set of parameters including transponder sub-channel gains and uplink EIRP of each transmitting terminal must be determined optimally. Different from the traditional link supportability analysis aiming at minimizing the total transponder output power, a maximal sum Shannon capacity optimization objective is raised subject to the basic link supportability constraints. Further, based on rigorous analysis and derivation, an efficient multilevel optimization (MO) algorithm is proposed to solve the optimization problem. Finally, an example is provided to verify the effectiveness of our proposal. Comparison results between our proposal and previous works show that, by the MO algorithm, not only all links´ supportability can be guaranteed but also a larger sum capacity with the global optimal solution can be achieved.