A Multiple User Satellite Communications Network Control Simulation

A synchronized (SYNC) network has been designed as a spread spectrum overlay of an existing communications system, EXCOM. These networks will share a direct multiple-access satellite transponder. The basic network, EXCOM, utilizes frequency division multiple access (FDMA) carriers with quadrature phase shift keyed (QPSK) modulation to which the SYNC network must appear as a stable noise floor across the entire transponder bandwidth. The SYNC network contains a centralized control system interfacing directly with the EXCOM control system. The EXCOM control system will specify the transponder power level available to the SYNC network. The SYNC control system must maintain this usage level to within ±1.0 dB, or the EXCOM control system will be triggered to readjust the EXCOM FDMA carrier power levels. To investigate the feasibility of meeting this requirement within the context of the SYNC network, a simulation has been performed. This paper out-lines the SYNC control problem and the predicted performance of the SYNC control system. The results suggest that the system is capable of satisfying the ±1.0 dB constraint placed on it by the EXCOM control system under the conditions assumed.