Adaptive bandwidth allocation methods in the satellite environment

The paper proposes two alternative bandwidth allocation schemes suited for the Ka-band satellite environment. The aim is to provide a control mechanism to compensate rain fade. The main idea is considering the effect of the attenuation as a reduction of the bandwidth 'seen' by a single land station and using a supplementary portion of bandwidth to guarantee a rain margin. One of the earth stations involved plays the role of master. It monitors the available resources and contains the Centralized Network Control Center, which manages the bandwidth allocation. Both schemes are organized in two hierarchical levels. The upper level, located in the master station, assigns a portion of the overall bandwidth to the earth stations. At each of these, the lower level shares the received portion between guaranteed and non-guaranteed traffic. The allocation mechanisms are aimed at keeping the call blocking probability of the guaranteed traffic below a given threshold and at reducing the packet dropping probability of the nonguaranteed, best-effort traffic. An extensive performance analysis has allowed investigating the behavior of the two strategies and to evidence the differences between them.