Experimental results with forward erasure correction and real video streaming in hybrid wireless networks

In a heterogeneous MANET, based on wireless LANs linked together by satellite, the overall channel efficiency is impaired by multiple effects, because of multipath fading in the terrestrial segment and atmospheric fading on the satellite link. In this paper we address this issue by applying forward erasure correction codes (FZC) to MPEG-4 video sequences exchanged by the hosts of a hybrid network, made of a satellite link and a wireless LAN using 802.11b devices. A standard video streaming application runs on one end of the satellite link while, at the other end, a wireless ad hoc network receives the multicast video stream. This work aims at demonstrating the improvement in Quality of Service (QoS) of the video transmitted in the hybrid network. The main parameters measured are the packet loss, the delivery delay, and the overhead in bandwidth occupancy imposed by the use of FZC. The received video is then evaluated by using a MOS (Mean Opinion Score) procedure.