Cross-layer study for resource management in DVB-S2 with mobile users

Recently there has been a renewed interest on mobile communications via satellite. Therefore, the DVB-S2/-RCS standard has been updated with some countermeasures to combat fading effects of the mobile scenario. The focus of this paper is on multimedia traffic management on the DVB-S2 forward link to collective terminals on trains. In our study, we consider ACM, PHY margins, and LL-FEC coding to counteract the time-varying propagation conditions in Ku-band that are very critical for the railway scenario. A multi-layer optimization study is performed in order to maximize TCP goodput by jointly tuning LL-FEC coding and the PHY layer margin. It is shown how, using appropriate parameters, LL-FEC coding can improve the performance of the system. Moreover, the performance of the proposed UBMT scheduler is evaluated in managing CBR and FTP traffic flows. This study has permitted to determine the maximum capacity of CBR flows (guaranteeing a given quality of service level) in the presence of FTP flows.