Survivable space networks: the physical layer

The authors address the physical layer of a survivable communication network built around a space segment. The physical layer consists of satellites and ground stations, as well as the cross and up/down links between them. The proliferated-network approach to survivability is considered. Survivability is obtained by adapting to losses rather than by preventing them. It is noted that while power and cost constraints prohibit extensive electronic communication countermeasures on individual links, judicious choices of modulation, coding and antenna patterns provide some level of protection from less determined interferers. Issues of antenna selection, signal processing, and physical-connection activation are examined. It is concluded that a network of proliferated, low-earth orbit satellites can provide a viable approach to realizing robust, cost-effective communications.<>