A combined resource allocation method for fade countermeasure and call admission control in satellite networks

Resource allocation is one of the main tasks in a network, where different users and services have to share a pool of common resources. Satellite networks, with respect to cabled ones, in addition have to face long propagation delays and variable channel conditions, mainly due to signal attenuation because of bad atmospheric events, particularly in the Ka band (20-30 GHz). In the work here presented we coordinate the actions taken at the physical layer, where the fade countermeasure technique is applied, with the work done at the data link layer, where we try to allocate the bandwidth according to an optimized policy. Two resource allocation methods, based on optimized adaptive complete bandwidth partitioning strategies, have been studied for a faded satellite network environment with multimedia traffic, simulated and compared between them and with a simple allocation scheme that does not apply any optimization criteria. In all the schemes presented the call admission control (CAC) policy for the real-time connections is administered locally at the traffic stations, while a master station is in charge of managing the bandwidth allocation policy. Figures of merit such as loss, blocking and dropping probabilities are computed for the three methods, in order to evaluate the performance of each system in the same network conditions. Numerical results are provided for a specific network architecture in a real environment, based on the Italsat satellite national coverage payload characteristics.