Cross-Layer Algorithm for VOIP Applications over Satellite

Abstract

It is proved that the normal suite of the TCP/IP protocols works well when it is used in terrestrial networks transporting real time applications. The situation is quite different when wireless networks are used for the same services; their susceptibility to errors, losses as well as the existing delay cause a degradation in the overall performance. Due to the existing demand to interconnect terrestrial networks with satellite communications using DVB-S2/DVB-RCS standards, the satellite link poses a challenge which is to overcome the problems mentioned when applications as Voice Over IP (VOIP) are considered.In the same context, cross-layer mechanisms are being used successfully in Ad-hoc networks. They propose interactions between layers different from the traditional ones in the protocol stack. These mechanisms provide a fast and better way to exchange parameters, drawing as a result a good option to improve the performance in wireless networks.This work proposes an innovative algorithm to adapt dynamically the coding for VOIP applications over satellite using a cross layer interaction between the application and network layers in order to improve the throughput and the perceived quality. This interaction with the network layer indirectly takes into account the state of the MAC and physical layers.