Multicast-Aware Power Allocation in Multiple Spot-Beam Satellite Communication Systems
February 01, 2006
In this paper, we address the problem of user heterogeneity in satellite multicast from the perspective of resource allocation in a multiple spot-beam satellite system that supports both unicast and multicast flows. Satellite communication systems, with their wide-area coverage and direct access to a large number of users, clearly have an inherent advantage in supporting multicast applications. In order to remain competitive against other broadband technologies, however, next generation satellite systems will be required to support both unicast and multicast flows and offer optimal sharing of system resources between these flows. We show that user heterogeneity across spot-beam queues may result in lower allocated session rates for active flows, and be perceived as unsatisfactory by potential users when both unicast and multicast flows are active in the system. We propose an optimization-based approach that allocates resources with the goal of smoothing user heterogeneity and show that resulting session rates are higher on the average for both unicast and multicast flows. This is achieved through the re-distribution of system power among spot-beam queues, by taking into account the load on the queues and the channel states. We conclude that it is possible to increase the average session rates of multicast flows by 25–100%, and the rates of unicast flows by 15–40% compared to the pre-optimization levels.