BEST DESIGN OF DEEP–SPACE COMMUNICATION WITH A 2–HOP DOWNLINK AT 32 GHz

We apply an optimum design to deep–space communication at Ka band and above, made with a 2–hop downlink trough a data relay satellite orbiting the Earth, with transparent transponder. The optimum requires that each hop be designed for providing half of the total noise–to-signal power ratio (twice the total signal–to-noise power ratio) tolerated for a given probability of symbol error. We have applied the optimum design equations to design a deep–space downlink at 32 GHz, at a distance of 2 astronomical units (about planet Mars) at Spino d’Adda, Gera Lario and Fucino, in Italy.