Assessment of effectiveness of signal-code constructions in time division-multi-access satellite systems

Energy losses in TDMA satellite circuits are investigated on the basis of the model of a Gaussian memoryless channel incorporating a signal code construction. The signal code construction is a consolidated two stage construction with a modulation system as the inner stage and correcting codes as the outer stage. Signal code constructions employing Gray codes, cascade codes and M-ary block codes are considered. Real TDMA systems are analyzed on the assumptions that the calculations are made using an audio frequency equivalent of the circuit, the relay carries a single trunk, the timing and carrier frequency synchronization is ideal, the signal is transmitted in the continuous stream, and there is no noise at the input of the receiving filter. The effectiveness of a signal code construction employing cascade codes on a real satellite link incorporating MDVU-40 equipment is modeled. The method can be used to select the signal code construction in a communications channel for the required data rate, and to maximize the energy gain and attainable transmission rate over the relay trunk.