Run-time satellite tele-communications call handling as dynamic constraint satisfaction

The next generation of communications satellites may be designed as a fast packet-switched constellation of spacecraft able to withstand substantial bandwidth capacity fluctuations due to causes ranging from unstable weather phenomena to intentional jamming. Scheduling and servicing call requests in such a dynamic environment requires real-time decisions with regard to allocation of resources including bandwidth, call routing and load balancing. In this paper, we present a general satellite communication scheduling domain, and describe a working implementation of an autonomous system for handling such dynamic scheduling problems. The solution approach is drawn from the area of dynamic constraint satisfaction problems (DCSP), which generalizes these and many other dynamic scheduling problems. We adapt DCSP techniques to the satellite communications domain, in particular solution repair and optimization by gradient-climbing. These reasoning methods respond to changes in the problem specification by repairing the current solution. As a result, they are anytime algorithms which can trade run-time efficiency for solution quality. This approach supports dynamic call requests; negotiation and fulfillment of prioritized Quality of Service (QoS) contracts; graceful degradation in the presence of dynamic call traffic, changes of priority schemes, and environmental conditions; and optimization of geometrically constrained resources.